A synoptic review of the ant genera (Hymenoptera, Formicidae) of the Philippines

Abstract An overview of the history of myrmecology in the Philippine archipelago is presented. Keys are provided to the 11 ant subfamilies and the 92 ant genera known from the Philippines. Eleven ant genera (12%), including 3 undescribed genera, are recorded for the first time from the Philippines. The biology and ecology of the 92 genera, illustrated by full-face and profile photo-images, of Philippine ants are summarized in the form of brief generic accounts. A bibliography of significant taxonomic and behavioral papers on Philippine ants and a checklist of valid species and subspecies and their island distributions are provided.


introduction
The study of ants can be difficult, particularly in the tropics. Tropical ant faunas are only partly explored and information concerning them is widely scattered throughout the scientific literature. Taxonomic references are frequently hard to access, badly outdated, and difficult for the non-specialist to use. The systematics of several major genera (e.g., Camponotus, Crematogaster, and Pachycondyla) is still chaotic and unrecognized synonyms and undescribed species abound. Taxonomic progress is relatively slow because most type material of described material is deposited in Europe, North America, or Japan, and museums are understandably hesitant to send fragile types to workers in the developing world (Naskrecki 2004).
Introductory accounts of important tropical ant faunas are badly needed to provide an entry point for biologists interested in studying ants. The purpose of this paper is to provide such an introduction to the ant fauna of the Philippines.
Simplified keys to subfamilies and to genera are presented. Most character states in the keys are discernible with a 40× stereomicroscope. Technical terms and subtle character states are minimized. Full-face and profile color photo-images are included to illustrate the different genera found in the Philippines. A glossary is also included to help the student understand the precise technical terms used in the keys. And the most up-to-date systematic arrangement of genera is used (Bolton et al. 2006, Bolton 2011. We hope that this paper will stimulate local interest in the study of Philippine ants.

A short history of Philippine myrmecology
The study of Philippine ant fauna began in the second half of the 1800's, during the last century of the Spanish colonial period. Small numbers of Philippine ants were collected by European travelers who then sold or gave their collections to the great myrmecologists of that era, notably Auguste Forel and Carlo Emery. Emery described ants collected in Manila and Antipolo, Luzon Island by E. Simon, a Frenchman (Emery 1893c). Frederick Smith described a few species from the Philippines without specifying the provenance of the specimens (F. Smith 1858). These researchers described some new species, but made no effort to characterize the Philippine ant fauna as a whole.
During the early American colonial era, Richard C. MacGregor, a US-trained Australian ornithologist, Charles S. Banks and other biologists working for the Bureau  (Ashmead 1904a(Ashmead , 1904b. Dr. Francis X. Williams, who studied under W.M. Wheeler, collected ants while he was looking for insect predators of agricultural pests, as a researcher for the USDA. He took advantage of the expertise of Dr. Charles F. Baker, a professor at the University of the Philippines College of Agriculture at Los Baños, Laguna. Baker collected insects prodigiously, amassing hundreds of Schmitt boxes, which were bequeathed to USNM (Evans 1985).
The first intensive ant collecting was done by Dr. James W. Chapman, Wheeler's colleague at Harvard, who arrived in the 1910's to be a missionary and teacher at Silliman University in Dumaguete, Negros Oriental Province, Negros Island. Chapman concentrated on studying the ants of the Cuernos de Negros Mountains, but also collected in northern Luzon and Mindanao. During the Second World War, he continued to collect ants even as Japanese soldiers were hunting him down. Fortunately, he survived capture and incarceration, and his collection, which he had hidden, was largely intact (Chapman and Chapman 1947). Most of these specimens, still in their original jars, are deposited in the Museum of Comparative Zoology (MCZ) at Harvard University. Chapman later published a list of the ants of Asia (Chapman and Capco 1951).
Interestingly, Jesuit priests were important early collectors of Hymenoptera, including ants. Ashmead studied the specimens collected by Fr. W.A. Stanton, S.J. and Fr. Robert E. Brown, S.J. (Ashmead 1904a(Ashmead , 1904b. Fr. Brown collected the holotype queen of the controversial genus Pseudaphomomyrmex, recently synonymized under the genus Tapinoma (Ashmead 1905, LaPolla and Longino 2006, Fisher and Bolton 2007. Fr. B.B. Lowery S.J. also collected ants in the Philippines in the 1960s (Rigato 1994, Ward 2001, Shattuck 2011. His collections have been studied by researchers all over the world. During the Commonwealth period and after the Second World War, some Filipinos also collected ants. This fact can be gleaned from the locality labels on specimens in certain museums. Specimens collected by Domingo Empeso, H.M. Torrevillas, A. Reyes, and M. Ramos are in the collections of the MCZ and the Bernice P. Bishop Museum in Hawaii. In 1966, Dr. Clare Baltazar published a monograph on Philippine Hymenoptera, which included 235 entries for ant species (Baltazar 1966).

Current status of Philippine myrmecology
Since the efforts of the late Dr. James W. Chapman in the 1920s to 1940s, there has been relatively little intensive collecting and the studies of ants in ecological research have been few (Calilung 2000, Caceres-Plopenio, unpubl. M.S. thesis). A recent transect study (Alpert and General, in prep.) surveyed the ants of a 27-year-old narra private reforestation project on the slopes of Mt. Isarog in the Bicol region of Luzon Island. New generic records and new species are recorded. A subsequent transect study by Joanaviva Caceres-Plopenio in a nearby area added more species distribution records and possibly new species (Caceres-Plopenio, unpubl. M.S. thesis; K. Eguchi, pers. comm.). More recently, Perry Buenavente conducted ant surveys on several mountains in Luzon and Mindanao during expeditions of the National Museum of the Philippines, accumulating many new collections (P. Buenavente, pers. comm.).
Inventories for undergraduate and graduate theses remain an important source of specimens, especially in unexplored study sites. Fortunately, the collection methods are now more standardized (Agosti et al. 2000), allowing the comparison of datasets from different localities. Government permits are required for any collecting of specimens on Philippine soil and export of the same. And the Philippine government is the perpetual owner of all specimens, including holotype specimens.
The study of Philippine ant diversity is still in its infancy. A cursory examination of the species list (see Appendix) shows a strong sampling bias in the known distribution of species. Luzon Island has at least 265 species while Mindanao Island, only slightly smaller in area, has but 99 recorded species. Neither island is close to being wellcollected. The large islands in the central Philippines, with the exception of Negros, namely Leyte, Mindoro, Panay, and Samar, are very poorly represented in the list. Any attempt at understanding the biogeography of Philippine ants is therefore premature.
Perhaps the best documented ant fauna in the Philippines is that of the Cuernos de Negros Mountains near Dumaguete City, Negros Island. This area was the favorite hunting ground of Chapman, who collected there for about two decades (Chapman and Chapman 1947). Nevertheless, with only 123 species known from Negros Island, more intensive and systematic collection methods will certainly turn up new species and new distributional records there.
Much has changed since the publication of Baltazar's monograph. Many of the genera have been revised, many species have been added to the list, and a number of names have been synonymized. This paper presents an updated list containing 474 valid species and subspecies names for ants in the Philippines.

Why study ants in the Philippines?
The high diversity of ants in the Philippines makes inventory studies interesting, with little of the monotony of encountering the same species over and over again. Ant surveys can detect the presence of invasive species and provide insights into the biogeography of the islands, a baseline for pre-operation inventories of mining sites and a measure of post-mining or post-logging remediation. There is much to be done and discovered, and many opportunities await the Filipino myrmecologist.
There are many interesting study sites in the Philippines. Particularly interesting are: old growth forests, old mangrove areas, small islands (preferably uninhabited), wooded ravines, reforested areas, and even microhabitats such as soil and forest canopies. Each island or province has its own opportunities. The ant faunas of the large central islands remain unexplored. Surprisingly, new species have been found in even the most disturbed localities, such as university campuses (DMG, unpub. notes), possibly relicts of a more diverse ant assemblage (S. Cover, pers. comm.).

Geographical and bio-climatic features of the Philippines
The Philippines is so ecologically diverse that it is very difficult to characterize the country in a single paragraph. While the climate is generally tropical and maritime, there are zones which are distinctly different. The mean temperature ranges from 25.5° C in January to 28.3° C in May, however, high-elevation locations (>1,000 masl) are sub-temperate. Baguio City, in northern Luzon, has a mean annual temperature of only 18.3˚C. Some parts, such as southern Cotabato Province, Mindanao Island, are relatively dry with an average annual rainfall of only 978 mm (PAGASA 2010). In contrast, 5713 mm of rainfall was measured at 1650 masl on Mt. Isarog in 114 days from November 1993 to May 1994 (Heaney et al. 1999). There are also wet tropical zones, mainly in the eastern part of the country, and dry tropical zones that are in the rain shadow (west) of mountain ranges. Camarines Sur, a province in the Bicol Peninsula of Luzon Island, for instance, has three distinct climate patterns, depending on elevation and position relative to Mt. Isarog, the dominant feature of the landscape. There is also a typhoon corridor, mainly in the eastern part of the archipelago, which is visited by an average of 19 typhoons every year (PAGASA 2010).
The Philippines is composed of over 7,100 islands, most of which are uninhabited. There are islands, such as Sibuyan Island in the central Philippines, which have never been connected to larger islands, even during the last Ice Age (Heaney et al. 1999). Single mountains, usually volcanoes, also exist as island habitats within the broader lowlands. This complex blend of climatic diversity and opportunity for geographic isolation has likely led to high levels of endemism, a phenomenon that deserves much further exploration. For example, two adjacent islands, Biliran and Samar, each have their own species of Meranoplus, a ground-dwelling myrmicine ant (Schödl 1998;DMG, unpub. notes). The Palawan island group is unique in that many of its plants and animals, including some ants, are found nowhere else in the Philippines, or in the world. Palawan Island is the type locality of the enigmatic leptanilline genus Noonilla.

Threats to Philippine ant diversity
The Philippines is considered one of the hottest of the biodiversity hotspots because of the severe human pressure on its highly endemic native flora and fauna. Time is running out for the the remaining primary forests. Despite decades of regulation and reforestation, forests continue to dwindle. For instance, all the privately reforested narra trees (Fabaceae: Pterocarpus indicus Willd.) of the study site of our 2003-4 transects (Alpert and General in prep.) had already been poached by 2009, wiping out 27 years of stewardship of the area. Even the stumps were removed (DMG, pers. obs.). Forest destruction seems to go on unabated, exacerbated by new large-scale mining projects that seem to target the mineral resources under primary forests.
Aside from habitat destruction, invasive ant species also impact the native ant assemblages, although the extent and severity of this influence is not known. In both urban and agricultural areas are found the worldwide invasive species, e.g., Solenopsis geminata (Fabricius 1804), Tapinoma melanocephalum (Fabricius 1793), and Paratrechina longicornis (Latreille 1802). Other invasive species have not been found, but this may be due to a lack of attention.

Some forest habitats in the Philippines
We include some images of intact and heavily damaged forests to illustrate the potentials and problems for ant research in the Philippines. The Philippine ant fauna is very poorly explored and records are few and spotty at best. A researcher can essentially choose a mountain among several hundred mountains, get the necessary permits and be the first one to study the ants on that mountain. However, that mountain may also be very disturbed or degraded, leaving only the tramp species that abound in disturbed habitats. In addition to environmental damage, there is also an active communist insurgency and other serious security threats to researchers in the field. Other areas may harbor malaria mosquitoes and other serious health threats. Hence, local collaboration is quite necessary to minimize the risks of field work in the Philippines.

Genus accounts of Philippine ant genera
In this contribution, the acronym "PH" is used to represent the archipelago of the Republic of the Philippines, in compliance with the International Organization for Standardization 3166-1 country codes (ISO 2010). The archipelago should also be        referred to as "the Philippines" not "the Philippine Islands". The expression "Philippine Islands" and the acronym "PI" are anachronisms and should no longer be used since they refer to the islands before the country gained independence in 1946.
The first electronic checklist of Philippine ants is available online at Discoverlife . Another online resource is the Philippine page on AntWeb, hosted by the California Academy of Sciences (Alpert and General 2008).
Because these are genus accounts, plural terms, e.g., "these ants" or "they" refer to species belonging to the genus. Singular terms, e.g., "this species" or "it" refers to a particular species in the genus. The genus account typically introduces Philippine material referable to the particular genus, then gives a brief description of the morphology or behavior of the ants belonging to the genus and finally suggests collecting techniques. Some behavioral aspects may be inferred from published studies of non-Philippine congeners.

Figs. 9 A, B
The single known valid Philippine species, Acanthomyrmex mindanao Moffett, 1986, was described from specimens collected under bark in Mt. McKinley, Davao Region, southern Mindanao Island. Other specimens were collected in northern Mindanao Island: Momungan, Olangon, and Iligan City, Lanao del Sur Province and Gingoog City, Misamis Oriental Province. This species is also known from Sarawak, Malaysia. These ants may be collected by sifting leaf litter, baiting with small seeds, and looking under bark. Keys to species: Moffett (1986) (World, revision), Agosti (1992) (World, revision), Terayama et al. 1998.

Genus Acropyga Roger, 1862
Formicinae: 40 spp., 3 known from PH. Figs. 9 C, D (New record). This genus is pantropical. These tiny, yellow, hypogaeic ants are known to tend subterranean coccids. One species known from the Philippines, Acropyga pallida (Donisthorpe, 1938), was originally described from New Guinea. These ants may be collected by sifting leaf litter and soil cores up to about 10 cm deep. Key to species: LaPolla (2004).

Genus Anochetus Mayr, 1861
Ponerinae: 87 spp., 13 known from PH. Figs. 10 E, F These small, fast-moving trap-jawed ants are general predators and usually found foraging singly on the ground or in the leaf litter. These ants are similar to Odontomachus, except that they are smaller and have blunt petiolar nodes. Key to species: Brown (1978) (World), Zettel (2012) (Philippine species).

Figs. 11 A, B
The worker caste of this enigmatic genus was recently discovered and described, including Anomalomyrma helenae Borowiec, Schulz, Alpert & Baňař, 2011from northern Palawan Island (Borowiec et al. 2011). These tiny subterranean ants have a petiole and postpetiole whose tergites and sternites are fused to form rigid tubes, a unique morphology among ants. These ants may be collected by leaf litter sifting and underground baiting near water sources.

Genus Anoplolepis Santschi, 1914
Formicinae: 14 spp., 1 known from PH. Figs. 11 C, D The species found in the Philippines, Anoplolepis gracilipes (F. Smith, 1857), is a pantropical invasive ant, with 11-segmented antennae with extremely long antennal scapes and a slender, constricted mesosoma in dorsal view. It is locally dominant around its nest. This species may nest in the ground or in a tree hollow. The myrmecophilous associations observed by the present authors indicate that this ant may be native to the Philippines. Upon opening a nest in a tree hollow, we found that muscoid flies immediately hovered over the scampering workers and the brood. In a coconut farm in Can-delaria, Quezon Province, DMG also observed and collected an immature reduviid bug mimicking the erratic movement, color, and size of this ant. It may be collected by carefully inspecting tree hollows and rotten logs, baiting with tuna and searching for trails of foraging workers on the ground and along branches. danao Island (Figs. 11 E,F) (DMG, unpubl. notes). These ants typically nest in rotten logs and the soil under the logs. These ants may be collected by pitfall trapping, breaking into rotten logs and searching for foragers on the ground.

Figs. 12 A, B
Ants of this genus may be confused with some Strumigenys species, but they have more than 6 antennal segments. These small, cryptic, slow-moving ants have clavate hairs all over the body. They forage in the leaf-litter. When disturbed, these ants roll up into a tight ball which makes them even harder to find. After about a minute, they stretch out and start walking slowly. There are specimens of an unidentified species from a transect study at Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). Specimens were collected at 550 meters. These ants may be collected by sifting leaf litter over a white sheet, waiting a while, and carefully inspecting seedlike objects that begin to walk slowly. Keys to species (as Eurhopalothrix):  (World); Taylor (1968Taylor ( , 1980Taylor ( , 1990b (Indo-Australian, Australasian), Baroni Urbani and de Andrade 2007 (synonymy of Eurhopalothrix under Basiceros).

Genus Calyptomyrmex Emery, 1887b
Myrmicinae: 25 spp., 2 known from PH. Figs. 12 C, D These small, cryptic, slow-moving ants bear a hard, thick integument with numerous evenly-spaced clavate hairs. They curl up into a ball when disturbed and are found in the leaf litter or on the ground. These ants may be collected by sifting leaf litter on a white sheet, waiting a while and carefully inspecting seed-like objects. After about a minute, these seed-like objects may stretch out and start to walk slowly. Keys: Baroni Urbani (1975) (Indian subcontinent); Bolton (1981) (Afrotropical); Shattuck (2011) (Southeast Asian revision).

Figs. 12 E, F
Camponotus is an extremely large genus in dire need of taxonomic revision. This is a widespread genus in the Philippines. Twenty-eight species are presently known from the Philippines, but this is probably only a fraction of the total. This genus is unusual among formicines in that the usual conspicuous ring of hairs around the acidipore is absent. This genus can be recognized by the placement of the antennal insertions, which are always set back (not adjacent to) from the posterior clypeal border. Cam-ponotus are often medium to large ants; dimorphic or polymorphic workers that forage along trails from their nest in wood. Some species are nocturnal. Mimicry also occurs in this genus. There is a single undetermined minor worker in the Philippine collection of the Bernice P. Bishop Museum that looks very similar to ants of the   A, B Calyptomyrmex beccarii Emery, 1887 C, D Camponotus albocinctus (Ashmead, 1905), major worker e, F.
genus Dolichoderus (GDA, unpub. notes). These ants may be collected by breaking into cavities in live wood or dead branches and searching for foragers on the ground, foliage, tree trunks and branches or in the canopy.

Figs. 13 A, B
This genus is known to have both normal winged and worker-like wingless males which fight and exhibit interesting courtship behavior (Heinze et al. 1993, Yamauchi et al. 2005, Mercier et al. 2007). These tiny, ground-and rock-dwelling ants bear the characteristic swollen postpetiole which is wider than long, and much larger than the petiole. Several species are pantropical tramps. There are 5 species known from the Philippines. One species, Cardiocondyla sima Wheeler, 1935b, is apparently widespread, reported in Lanao Province, Mindanao Island and in Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These ants may be collected by leaf litter sifting, pitfall trapping and baiting with cookie crumbs on exposed rocks in creeks and rivers and following the forager to its nest in the rock's crevices. Key to species: Seifert (2003) (Selected species-groups only).

Genus Carebara Westwood, 1840
Myrmicinae: 175 spp., 3 known from PH. Figs. 13 C, D The Philippine species of this pantropical genus are poorly known. There are specimens of two unidentified species from a transect study at Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). Other species have been collected on Samar Island and in Misamis Occidental Province, Mindanao Island. These are very tiny ants with dimorphic workers. The major workers may possess a pair of tubercles or horns near the posterior margin of the head. These ants are ground-dwelling and may be collected by sifting soil and leaf litter. Key to species: Fernandez (2004) (New World only), Fernandez (2010) (description of first Philippine species).

Genus Cataulacus F. Smith, 1853
Myrmicinae: 69 spp., 3 known from PH. Figs. 13 E, F These robust, hard-bodied ants have a wide, sculptured head and the antennal scrobe passing below the eye. They are known to be arboreal, can glide back to the tree trunk when they fall (Yanoviak et al. 2008) and nest in small hollow twigs or rotten branches of live trees. These ants may be collected by searching dead branches still attached to the tree and beating low vegetation over a white sheet. Key to species: Bolton (1974) (World revision).

Figs. 14 A, B
Centromyrmex feae (Emery, 1889) is the only species recorded from the Philippines at present. These small, cryptic ants have a pronotum that is somewhat flattened dorsally, mandibles that sharply curve downward and backward (in side view), and middle tibiae with strong peg-like setae. The workers are weakly polymorphic, with slight differences among nestmates. They are hypogaeic. Some evidence indicates that they are associated with termites. These ants may be collected by sifting leaf litter and soil cores at least 10 cm deep.

Genus Cerapachys F. Smith, 1857
Cerapachyinae: 144 spp., 11 known from PH. Figs. 14 C, D These hard-bodied ants have a large, globular petiole and a larger, barrel-shaped postpetiole. They are predators on other ants and some species conduct group raids on other ant nests. During a raid, they steal the larvae and pupae which they sting. These stung prey remain alive for a long time, providing fresh food for the colony. In Mt. Isarog, Bicol Region, Luzon Island, they have been found nesting in twigs, with a larder of pupae of another ant genus, Crematogaster (Alpert and General in prep.). These ants may be collected by breaking open twigs on the ground and in the leaf litter, sifting leaf litter, and searching for columns of raiding workers. Key to species: Brown (1975) (World).

Genus Chronoxenus Santschi, 1919
Dolichoderinae: 46 spp., 2 from PH. Figs. 14 E, F Dubovikov (2005) recently revived this genus from synonymy to receive all Oriental species of Bothriomyrmex Emery, 1869b. A specimen of an unidentified species, collected from Palawan Island in 1925, is in the ant collection of the Museum of Comparative Zoology, Harvard University. There are specimens of an undetermined species, collected in Laguna Province, Luzon Island, in the Insect Collection of the International Rice Research Institute. An excellent nest series with all the castes of possibly another species was recently collected by Perry Buenavente from Mt. Diwata, Agusan del Sur Province, Mindanao Island. These small ants, superficially similar to Tapinoma, have a petiole with an erect scale; with short, indistinct palps and a propodeum with a short dorsal face and a long declivity. These ants may be collected by sifting leaf litter including the humus layer. Emery (1925) (out of date); Shattuck (1992c) (generic revision of subfamily). These small ants have a characteristically heart-shaped gaster that can flex over the mesosoma. They are often associated with coccids and aphids, sometimes building carton or soil shelters over these sap-sucking insects. They may be hypogaeic, epigaeic or arboreal. Similar to Cataulacus, they can glide back to the tree trunk when they fall, earning the nickname "acrobat ants" (Yanoviak et al. 2008). These ants may be collected by breaking open carton or soil that is at the apices of young branches, sifting leaf litter and soil, inspecting plant roots, beating low vegetation over a white sheet, and baiting with peanut butter on tree trunks or cookie crumbs on the ground. Key: Hosoishi and Ogata (2009a) (subgenus Physocrema); Hosoishi and Ogata (2009b) (checklist of Asian species).

Genus Dacetinops Brown & Wilson, 1957
Myrmicinae: 7 spp., 1 known from PH. Figs. 15 C, D (New record). Dr. Herbert Zettel (Natural History Museum, Vienna, Austria) has a single specimen, tentatively identified as Dacetinops cirrosus, collected near Calbiga-a River, Mt. Pangasugan, Baybay, Leyte Island. These ants bear spongiform tissue on the ventral surfaces of the petiole, postpetiole, and the first gastral segment. They nest in rotten wood. These ants may be collected by sifting leaf litter and breaking into rotten twigs and wood on the forest floor. Key to species: Brown and Wilson (1957), Taylor (1985) (Papuasian).

Figs. 15 E, F
This genus is long overdue for revision. These ants are easily distinguished from other ponerines by the distinctive costate sculpturing that covers the head, mesosoma, and the petiole, which has 2 dorsal spines. The late Dr. W.L. Brown, Jr. believed that male characters may hold the key to producing stable species boundaries. These large black ants are ground-dwelling or arboreal and hunt singly for prey. Ants of this genus have a unique social structure in which the queen caste is absent and all workers have the potential to mate and lay eggs. Peeters and Higashi (1989) (reproductive dominance behavior).

Figs. 16 A, B
These small hard-bodied ants have the upper corners of the head drawn into broad points and have a distinctive barrel-shaped petiole. They are known to be arboreal but may forage on the ground as well. An unidentified species is reported from a transect study at Mt. Isarog, Camarines Sur Province, Luzon Island (Alpert and General in prep.). These ants may be collected by beating low vegetation over a white sheet and inspecting dead branches still attached to the tree for nests.

Genus Discothyrea Roger, 1863
Proceratiinae: 32 spp., 5 known from PH. Figs. 16 C, D (New record). There are specimens of Discothyrea bryanti (Wheeler, 1917) and D. clavicornis (Shattuck, pers. comm.) from adjacent stations of a transect study at Mt. Isarog by Joanaviva Caceres-Plopenio in 2006. This is remarkable because few species of this genus are sympatric, much less on the same transect (Shattuck, pers. comm.). Another unidentified species was found from a different transect study at Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). Specimens were collected at 550-700 meters above sea level. Two unidentified species were extracted from lowland forest leaf litter berlesate from Samar Island. Another unidentified species was collected from Palawan Island. These small cryptic ants have an extremely large apical antennal segment and the petiole broadly attached to the gaster. They are known to be predators of arthropod eggs. These ants may be collected by sifting leaf litter, pitfall trapping, and searching for nests under rocks. Brown (1958) (generic revision).

Figs. 16 E, F
The most common species, Dolichoderus thoracicus, is the black, hard-bodied ant usually associated with the locally-popular fruit of the lanzones tree (Meliaceae: Lansium domesticum Corr.), and of the makopa tree (Myrtaceae: Syzygium samarangense (Blume) Merrill and Perry) tending the mealybugs (Hemiptera: Sternorrhyncha: Pseudococcidae) that are found in the fruit bunches (DMG, pers. obs.). This ant, which forages day and night, is also common in urban and highly disturbed areas. These ants are easy to collect, with newly-mated queens even venturing indoors at night (DMG, unpubl. notes).

Figs. 17 A, B
Specimens of two unidentified species were collected from low vegetation in a transect study in Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). One of these unidentified species was collected by nocturnal beating of low vegetation. These hairy or fuzzy ants are unique in appearance and have hard bodies and petioles armed with teeth or denticles laterally. These ants may be collected by beating of low vegetation over a white sheet and inspecting of dead branches in the foliage and canopy.

Figs. 17 C, D
Euprenolepis negrosensis (Wheeler, 1930b) is known from the Philippines. It is rarely collected, perhaps because its tiny eyes indicate a subterranean life-habit. An unidentified species is depicted in Figs. 17 A, B. These ants have strongly curved man- dibles such that the apical tooth is directed posteriolaterally. They forage underground, or in the leaf litter and on the ground, possibly for mushrooms, as found by Witte and Maschwitz (2008) in Malaysia. These ants may be collected by sifting leaf litter, pitfall trapping, soil core sampling and possibly by baiting with edible mushrooms. Key to species: LaPolla (2009) (World revision).

Figs. 17 E, F
This genus was previously known only from the type species, Forelophilus overbecki Kutter, 1931, described from Java. Two widespread species are now known from the Philippines, F. stefanschoedli Zettel and Zimmerman, 2007 known from the islands of Luzon, Leyte, and Mindanao, and F. philippinensis Zettel and Zimmerman, 2007 known from the islands of Luzon, Bayagnan, and Mindanao (Zettel and Zimmerman 2007). An unidentified third species is shown in Figures 17 E, F. These ants may be collected by beating low vegetation over a white sheet and hand collecting from foliage.

Figs. 18 A, B
(New record). Gauromyrmex acanthinus (Karavaiev, 1935) is known from the Philippines. A single identified specimen is deposited in the MCZ Ant Collection. These small ants have a petiole with dorsolateral corners produced into acute angles or denticles. They are arboreal and may be collected by baiting with tuna or honey and by inspecting dead branches of live trees. Diagnosis: Bolton (2003).

Figs. 18 C, D
Gesomyrmex luzonensis (Wheeler, 1916) is known from the Philippines. This ant is rarely collected but widespread, having been collected in a bamboo grove in Los Baños, Laguna Province, Luzon Island and in a hardwood cavity nest in Cuernos de Negros, Negros Island. All members of this genus are presumed to be nocturnal and arboreal in habitat. These ants have large bean-shaped eyes and mandibles that look like pinking scissors. They are polymorphic, with major, media, and minor workers. Wheeler (1930c) quoted J.W. Chapman's description of the habits of G. luzonensis. Chapman found that the minors conduct most of the foraging, are attracted to ripe bananas, and are very timid. Key to species: Cole (1949); see also Wheeler (1929aWheeler ( , 1929bWheeler ( , 1930a.

Figs. 18 E, F
These hard-bodied ants are specialized predators of other ant species. At least one species, Gnamptogenys menadensis (Mayr, 1887), has mostly fertile laying workers instead of a queen , Gobin et al. 1999. They may be grounddwelling or arboreal, diurnal or nocturnal. These ants may be collected by breaking open rotten wood on the ground, inspecting cavities in living trees and dead branches, sifting leaf litter, and pitfall trapping. Key to species: Lattke (2004) (SE Asia and Australasia).

Figs. 19 A, B
These large cryptic ants bear characteristic long pliers-like mandibles and large eyes. They are usually ground-dwelling and hunt prey such as crickets in the leaf litter. A specimen of an unidentified arboreal species was collected on Mt. Isarog, Bicol Region, Luzon Island (DMG, unpubl. notes). These ants may be collected by sifting leaf litter, searching on the ground, and pitfall trapping.

Figs. 19 C, D
The taxonomy of this large pantropical genus is currently chaotic. These small, cryptic ants are very similar to Pachycondyla, but lack a second simple spur on the hind tibia. They have a simple ventral process of the petiole, without a fenestra or posterior angles as in Ponera. These ants make small colonies in soil, rotten wood, and leaf litter. These ants may be collected by sifting leaf litter, beating low vegetation, pitfall trapping, and searching in rotten wood. There is no modern key to species, however, Barry Bolton is currently revising this genus (B. Bolton, pers. comm.).

Figs. 19 E, F
These fast-moving ants may be confused with Dolichoderus but have a thinner cuticle and bear the characteristic wavy anterior clypeal margin. A specimen of Iridomyrmex anceps (Roger, 1863) was recently collected from Marinduque Island by Joanaviva Caceres-Plopenio (P. S. Ward, pers. comm). There is a specimen of one unidentified species, collected from Baguio, Benguet Province, Luzon Island, in the MCZ ant collection. Other unidentified specimens have been collected from the provinces of Pangasinan, Isabela, and Camarines Sur on Luzon Island, and the islands of Camiguin and Semirara. They are ground-dwelling and usually form large colonies. These ants may be collected by sifting leaf litter, pitfall trapping, and baiting on the ground. Key to species: Heterick and Shattuck (2011) (World revision).

Genus Lepisiota Santschi, 1926
Formicinae: 131 spp., 2 known from PH. Figs. 20 A, B These small, yellow or brown arboreal ants are characterized with a distinct angulate propodeum. They have been collected in the islands of Luzon, Negros, and Palawan, but rarely. These ants may be collected by beating low vegetation over a white sheet and inspecting cavities in living wood and dead branches in the canopy.

Genus Leptanilla Emery, 1870
Leptanillinae: 43 spp., 1 known from PH. fully exposed antennal socket and a swollen postpetiole. They are extremely difficult to collect, perhaps because they live deep in the soil. Soil cores 10 cm deep during transect studies at Mt. Isarog failed to turn up any leptanilline ants (Alpert and General in prep.). These ants may be collected by sifting soil cores up to 30 cm deep and underground baiting with centipede carcasses. Key to species: Baroni Urbani (1977b) (World), Ogata et al. (1995).

Genus Leptogenys Roger, 1861
Ponerinae: 248 spp., 11 known from PH. Figs. 20 D, E These long-bodied and slender ants bear the characteristic clypeus extending forward to form a rounded triangle. They also exhibit army ant-like behavior with large raiding columns and are known to prey on termites. They usually have worker-like, or ergatoid, queens and nest in rotten wood, under rocks, and in the ground. These ants may be collected by sifting leaf litter, flipping over rocks, pitfall trapping, and searching for raiding columns. Key to species: Wilson (1958) (Melanesian and New Caledonia).

Figs. 21 A, B
This genus occurs mostly in Australia, New Guinea, New Caledonia, and Aru Island, Indonesia. Leptomyrmex is unique in the subfamily in having an elongated head, mesosoma, and legs. In addition, most of the queens are wingless. A single specimen of Leptomyrmex fragilis (F. Smith, 1859) has been found in the Bernice P. Bishop Museum collection. The specimen was collected by L.W. Quate in 1959 in San Francisco, Agusan del Sur Province, Mindanao Island. Lucky and Ward (2010) consider this specimen a doubtful record, however it is validated by the many legitimate records of other insects in the Quate collection. These ants may be collected by sifting leaf litter, pitfall trapping, baiting on the ground, and searching for nests at the base of trees and in rotten wood. Key to species: Lucky and Ward (2010). Generic review: Shattuck (1992c).

Genus Liomyrmex Mayr, 1865
Myrmicinae: 1 sp., 1 known from PH. Figs. 21 C, D This is a monotypic tropical genus, with only one widespread species. Liomyrmex gestroi (Emery, 1887b) is known from throughout Southeast Asia. In the Philippines, it has been recorded from the islands of Luzon, Mindanao and Negros. This small, blind species has a smooth, almost hairless, body and bear large ventral processes on the petiole and postpetiole. It is assumed to be a kleptoparasite of mound-building termites, having been found inside live termite mounds and in forest leaf litter with termites. It may be collected by sifting leaf litter, pitfall trapping, and breaking into termite mounds to find nests. Rigato and Bolton (2001) (World revision).

Figs. 21 E, F
Lophomyrmex bedoti was collected by general collecting in Palawan. These monomorphic ants are hunter/scavengers, preying on various arthropods on the forest floor. They nest near or at the base of trees and form persistent soil-walled trails (similar to the trails of Pheidologeton ants), which may also run underground. These ants may be collected by baiting with sugar or protein bait and searching for nests at the base of trees and for conspicuous trails on the forest floor. Key to species: Rigato (1994) (World revision), Bharti and Kumar (2012) key to bedoti species-group.

Figs. 33 A, B
Taylor (2012) recently described four new species from the Philippines:one species from Leyte Island and three sympatric species from Mt. Isarog Natural Park, Luzon Island. A specimen of an unidentified species was collected in a transect study in Bulacan Province, Luzon Island. These small monomorphic ants are variable in morphology but usually have a prominently convex pronotum. They forage in the foliage and on the ground. Little is known of their biology. These ants may be collected by beating low vegetation, sifting leaf litter, flipping rocks and breaking into rotten wood for nests. Taylor (2012) (descriptions and images of Philippine species).

Figs. 22 C, D
The species known from the Philippines, Mayriella transfuga Baroni Urbani, 1977a, is wide-ranging in the Asian tropics and was originally described from Nepal. Ants of this genus are tiny, hard-bodied ants with a clypeus that extends as two lobes over the mandibles. The head and mesosoma are usually heavily sculptured while the gaster is smooth. They forage on the ground and nest in rotten wood and under stones. These ants may be collected by sifting leaf litter, pitfall trapping, and flipping stones and breaking into rotten wood for nests. Key to species: Shattuck and Barnett (2007) Schödl, 1998, is known from Biliran Island. There are specimens of another, possibly undescribed, species from the nearby island of Samar (Figs. 22 E,F). These slow-moving ants have the characteristic shield-like upper surface of the mesosoma, which is actually an extension of the pronotum. When disturbed, they curl up and remain motionless, similar to Basiceros and Calyptomyrmex ants. They are ground-dwelling generalist scavengers or seed predators and forage on the ground an in the foliage. They may be collected by beating low vegetation, sifting leaf litter, pitfall trapping, baiting with tuna or honey on trees, and searching for a ring of seed hulls around the nests. Key to species: Schödl (1998) (Oriental).

Figs. 23 A, B
The two Philippine species are known only from winged reproductives. An unidentified species is present in the Bernice P. Bishop Museum ant collection. These hard-bodied cryptic ants are commonly mistaken for ponerine ants because of their large, broadly attached postpetiole. They have deep antennal scrobes and the clypeus projects forward as a square lobe. They are often found feeding on hardwood termites in dead logs and are very rarely collected. These ants may be collected by breaking into the heartwood of hardwood logs that are suspended off the ground. Key to species: Wheeler (1919c) (World), Alpert (2007) (Madagascar).

Genus Monomorium Mayr, 1855
Myrmicinae: 399 spp., 5 known from PH. Figs. 23 C, D These tiny, smooth and slender ants have a single strong seta on the anterior clypeal margin. This genus includes worldwide invasive species such as M. pharaonis (Linnaeus, 1758) and M. floricola (Jerdon, 1851). They are typically opportunistic predators and scavengers. Their ground-nests are usually marked by a small crater of excavated soil. They may be collected by sifting leaf litter and pitfall trapping and searching for their nests on the ground. Key to species: Heterick (2001) (Australian).

Genus Myopias Roger, 1861
Ponerinae: 36 spp., 5 known from PH. Figs. 23 E, F These cryptic ants have eyes that are very close to the base of the mandibles, and usually have a clypeal extension visible in the large gap between the mandibles. They nest in rotten twigs and logs and forage in the leaf litter and on the ground. They are known to prey on springtails, millipedes, and even other ants. These ants may be collected by sifting leaf litter and breaking into rotten wood. Willey and Brown (1983) (Australasian).

Figs. 24 A, B
The sole species, Myopopone castanea (F. Smith 1860b), is widespread in the Philippines. This large-headed species has the characteristic flattening of the antennal flagella. It nests in Zorapteran-stage rotten wood, apparently preying on beetle larvae. It may be collected by breaking open rotten logs that you can dig into with a garden trowel. Brown (1960) (World revision).

Figs. 24 C, D
This genus is widespread throughout the Philippines. There are specimens of several unidentified species from different transect studies on Mt. Isarog, Bicol Region, Luzon Island (Samson et al. 1997, Caceres in prep., Alpert and General in prep.). One of these species is smooth and reddish-orange and can be mistaken as Pristomyrmex ants. There are also specimens of another species from transect studies in the provinces of Bulacan and Nueva Vizcaya, Luzon Island. Specimens of yet another unidentified species were collected in Palawan Island. These hard-bodied ants have the characteristic ventral ridge of the head, running from the back of the head to the base of the mandibles, and the distinctive barrel-shaped petiole. They nest in twigs and rotten wood or under rocks and forage in the leaf litter. These ants may be collected by sifting leaf litter, pitfall trapping, and flipping over rocks.

Genus Myrmicaria Saunders, 1842
Myrmicinae: 67 spp., 3 known from PH. Figs. 24 E, F These relatively large ants bear the characteristic 7-segmented antennae and long anterior peduncle of the petiole. They form conspicuous columns, forage on the ground and in the foliage, and are locally dominant where they occur. They are fairly easy to collect by baiting with tuna or honey, pitfall trapping, beating low vegetation, and hand collecting. Santschi (1925)   soil particles stuck to their body, providing perfect camouflage. When disturbed, adults lie motionless. They nest under rocks and in rotten wood. These ants may be collected by sifting leaf litter, flipping over rocks, and breaking into rotten logs. Brown (1960) (World revision), Bihn and Verhaagh (2007) (Indo-Australian, with tabular key).

Genus Noonilla Petersen, 1968
Leptanillinae: 1 sp., 2 known from PH. Figs. 25 E, F Described from an alate male reproductive, collected in southern Palawan Island, Noonilla copiosa Petersen, 1968 is the only described species of this genus. Ogata et al. (1995) examined a male specimen from Misamis Oriental Province, Mindanao Island and considered this genus incerta sedis in the subfamily. Bolton (2003) excluded the genus from Formicidae. However, Marek Borowiec (pers. comm.), who is currently studying the subfamily, is convinced that Noonilla belongs to Leptanillinae. These ants may be collected by sifting soil cores up to 30 cm deep, underground baiting for workers, and Malaise trapping for alates. Ogata et al. 1995, Bolton (2003 (synopsis of Formicidae).

Figs. 26 A, B
This genus was recently revived from synonymy by LaPolla et al. 2010. There are at least 3 unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.), including a morphological mimic of Tapinoma melanocephalum. These ants typically forage in the foliage, on the ground and in the leaf litter. They feed on honeydew from scale insects and aphids, and scavenge dead insects. These ants may be collected by beating of low vegetation, sifting leaf litter, pitfall trapping, and hand collecting. LaPolla et al. 2010 (Generic key to Prenolepis genus-group).

Figs. 26 C, D
The only species known from the Philippines, Ochetellus glaber (Mayr, 1862), is widespread in the archipelago. These fast-moving ants have a concave anterior clypeal margin and a concave propodeum. They may be arboreal or ground-foraging, sometimes forming conspicuous columns. These ants may be collected by beating of low vegetation, sifting leaf litter, and pitfall trapping. Shattuck (1992a) (generic revision).

Genus Odontomachus Latreille, 1804
Ponerinae: 65 spp., 11 known from PH. Figs. 26 E, F These large, big-headed, trap-jawed ants are commonly referred to as "hantik" in many Philippine dialects. They are aggressive, locally dominant and ground-dwelling but may also climb the foliage to hunt for prey. One species, Odontomachus malignus F. Smith, 1859, is known to nest in rock crevices that are regularly inundated during high tide, whence they emerge and forage for animals trapped in the intertidal zone. Ants of this genus may be collected by baiting with tuna, beating of low vegetation, pitfall trapping, and hand collecting. Keys to species: Brown (1976) (World), Sorger and Zettel (2011) (Philippine species).

Figs. 27 A, B
Odontoponera denticulata (F. Smith, 1858) is widespread in the Philippines. This moderately large, hard-bodied species has large blunt teeth on the sides of the pro- notum and a crenulate anterior clypeal margin. It nests under bare ground and hunts singly. The nest entrance is a simple hole just large enough for one worker to pass through. This ant may be collected by sifting leaf litter, pitfall trapping, and hand collecting. Wheeler and Chapman (1925), Creighton (1929) Viehmeyer, 1916a (N.B. This is a specimen from Singapore. The Philippine specimen has its head crushed on its right side and the mesosoma is damaged as well.) e, F.

Figs. 27 C, D
Oecophylla smaragdina is widespread in the Philippines. This large yellow-green species weaves silken nests among the leaves of mango (Anacardiaceae: Mangifera indica L.) and other trees. It is aggressive and dominant where they occur, effectively excluding other ant species in the trees and on the ground as well. A single colony may construct many nests among several trees, with the outer nests serving as defensive bivouacs for older workers and the inner nests containing the queen and brood. Ilokanos, many Southeast Asian tribes, and south Chinese tribes harvest the pupae as a delicacy. This species is usually found at elevations below 500 meters. It may be collected by searching for nests in the canopy and hand collecting from the tree trunks.

Genus Overbeckia Viehmeyer, 1916a
Formicinae: 1 sp., 1 known from PH. Figs. 27 E, F (New record). There is only one valid species in this genus, Overbeckia subclavata. This species has an antenna that gradually widens to a relatively broad terminal segment, and has a mesosoma that is flat and pinched at the metapleural spiracles. It was previously known only from Singapore, but a specimen in the MCZ Ant Collection is labeled "Bu of Sci, PI" and was collected by a certain M. Ramos (probably Maximo Ramos, who collected botanical specimens for the Bureau of Science from 1904 to 1932) (Van Steenis-Kruseman, 2006). "PI" is the abbreviation for Philippine Islands, the old name used during the American colonial period. O. subclavata is a very rare ant, and its rediscovery will be an important event in Philippine myrmecology. This ant species is assumed to be arboreal because of its relatively large compound eyes. It may be collected by beating low vegetation over a white sheet and inspecting dead branches of living trees.

Figs. 28 A, B
This large genus is also in dire need of taxonomic revision. These are small or large ants with two tibial spurs, a large pectinate spur behind a small simple one. They are abundant in the leaf litter and on the ground, hunting singly. They may be collected by sifting leaf litter, pitfall trapping, and baiting with honey or tuna bait. The genus Cryptopone was recently synonymized under Pachycondyla by MacKay and MacKay (2010).

Figs. 28 E, F
There are ten valid species in this Oriental and Indo-Australian genus, with three species known from the Philippines. These large arboreal ants have a pronotum with a flat dorsal outline. They are rare, and may be collected by beating low vegetation over a white sheet and inspecting tree hollows and dead branches in the canopy. Key to species: Bolton (1988) (World).

Figs. 29 A, B
As revised by LaPolla et al. (2010), this genus now contains only one species, the invasive species, Paratrechina longicornis (Latreille, 1802), widespread throughout the Philippines. The species readily invade households, farms and other highlydisturbed areas, recruiting large numbers of nestmates to scavenge dead insects and small animals and even table scraps. It may be collected by sifting leaf litter, pitfall trapping, and baiting with honey or tuna bait. LaPolla et al. 2010 (Generic key to Prenolepis genus-group).

Genus Pheidole Westwood, 1839
Myrmicinae: 1,121 spp., 21 known from PH. Figs. 29 C, D There are specimens of several unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). There are also unidentified species from transect studies in Isabela Province, Luzon Island and the islands of Samar and Mindanao. These tiny to small ants have the following charac- ter states: dimorphic, with large-headed major workers possessing usually edentate mandibles; pronotum strongly humped; and antennal club usually 3-segmented. They are ground-dwelling and forage on the ground and in the leaf litter, and may be collected by sifting leaf litter, pitfall trapping, and baiting with cookie crumbs.

Genus Pheidologeton Mayr, 1862
Myrmicinae: 49 spp., 5 spp. and 4 subspp. known from PH. Figs. 29 E, F This is another genus which needs taxonomic revision. These tiny to small ants form conspicuous raiding columns, often protected by low walls of soil. They are extremely polymorphic with a continuous series of intermediates. Superficially similar to Pheidole, they can be distinguished by their 2-segmented antennal club and their polymorphism. And unlike Pheidole, the major and supermajor workers join the foraging column. They are ground-dwelling, and may be collected by sifting leaf litter, pitfall trapping, baiting with honey or tuna bait, and hand collecting. Ettershank (1966).

Figs. 30 A, B
Philidris myrmecodiae (Emery, 1887) was reported from Mt. Isarog, Camarines Sur, Luzon Island by Samson et al. (1997). There are specimens of an unidentified species, collected from Zamboanga, Mindanao Island, in the MCZ Ant Collection. There are also specimens from a transect study conducted in Isabela, Luzon Island. An entire nest series of an unidentified species was recently collected from a small island off eastern Mindanao (DMG, unpubl. notes). These small polymorphic ants are superficially similar to Iridomyrmex but have their eyes very low on the head. They nest in rotten wood or carton above the ground and in swollen specialized plant structures called domatia, which workers defend vigorously (Shattuck and Barnett 2010). They may be collected by beating low vegetation over a white sheet and inspecting the swollen bases of epiphytic plants. Shattuck (1992aShattuck ( , 1992b.

Genus Plagiolepis Mayr, 1861
Formicinae: 86 spp., 2 known from PH. Figs. 30 C, D (New record). There are specimens of an unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.) and of other species from transect studies conducted by Perry Buenavente in the provinces of Isabela and Nueva Vizcaya, Luzon Island. These tiny, cryptic ants have 11-segmented antennae and long palps. They nest in the ground under rocks and in rotten wood and forage in the leaf litter, on the ground, and in the foliage. These ants may be collected by sifting leaf litter, pitfall trapping, and beating low vegetation over a white sheet. Brown (1973).

Figs. 30 E, F
There are 46 valid species, including three from amber, in this cosmotropical genus. There are four valid species known from the Philippines. These ants have a shagreened or dull body surface and two pectinate tibial spurs on the hind leg. They may be ground-dwelling or nesting in trees, and are often found hunting individually. They may be collected by sifting leaf litter, pitfall trapping, and hand collecting on tree trunks. Key to species: Brown (1975)

Figs. 31 A, B
This is the largest ant genus in the Philippines. There are specimens of several unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These small to large ants have spines on the pronotum, mesonotum, propodeum, or petiole or a combination of locations. They may nest in the ground, rotten logs or tree hollows. Some species are also known as weaver ants because they build nests in the foliage from larval silk and chewedup plant fibers. These ants may be collected by beating low vegetation over a white sheet, pitfall trapping, and inspecting tree hollows and dead branches in the canopy. Keys: Hung (1967), Dorow (1995), (World, subgenera); Bolton (1975), Kohout (1987) (sexspinosa species-group), Dorow and Kohout (1995), Kohout (1998), Kohout (2006a) (cryptoceroides species-group), (2006b) (parabiotica species-group). Natural history: Dorow et al. 1990.

Genus Ponera Latreille, 1804
Ponerinae: 55 spp., 2 known from PH. Figs. 31 C, D These tiny cryptic ants may be confused with Hypoponera or Pachycondyla, but have a fenestra or translucent window in the ventral petiolar process. They forage in the leaf litter and on the ground and nest in rotten wood and under rocks. These ants may be collected by sifting leaf litter, pitfall trapping, breaking into rotten wood, and flipping over rocks. Key to species: Taylor (1967) (World, revision).

Figs. 31 E, F
There are specimens of an unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These ants have the following character states: very long antennal scapes, at least half the length extending beyond the back of the head; mandibles not strongly curved, so that the apical tooth points to the side; and mesosoma elongated and constricted at midlength. They are groundforaging. These ants may be collected by sifting leaf litter and pitfall trapping. LaPolla et al. 2010 (Generic key to Prenolepis genus-group).

Figs. 32 A, B
Prionopelta kraepelini Forel, 1905 was collected from a botanical transect study on Samar Island. This species is widespread, also known from several locations on the

Genus Pristomyrmex Mayr, 1866b
Myrmicinae: 56 spp., 18 known from PH. Figs. 32 C, D There are specimens of an unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These small attractive ants have the following character states: mandibles that are twisted so that the edges oppose each other; and exposed antennal sockets. They nest in rotten wood on the ground or under rocks and forage in the leaf litter and on the ground. These ants may be collected by sifting leaf litter, pitfall trapping, breaking into rotten logs and flipping over rocks. Keys to species: Wang (2003) (World revision), Zettel (2006Zettel ( , 2007 (Philippine species).

Figs. 32 E, F
One species is known from Negros Island, Probolomyrmex dammermani. There are specimens of an unidentified species collected by Joanaviva Caceres-Plopenio from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Eguchi, pers. comm.; DMG, unpubl. notes). These tiny, cryptic ants have no eyes and bear their thick antennae on a shelf projecting forward from the head. They forage in the leaf litter and presumably also in the soil. These are among the rarest ants in the world. These ants may be collected by sifting leaf litter. Status of genus: Brown (1975). Keys to species: Taylor (1965), Eguchi et al. 2006.

Figs. 33 A, B
The species known from the Philippines, Proceratium papuanum Emery, 1897a, was collected from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These tiny ants have the following character states: apical segment of the antenna not extremely large or bulbous; and the petiole narrowly attached to the gaster. The workers forage in the leaf litter and on the ground. They may be collected by pitfall trapping and sifting leaf litter. Key to species: Baroni Urbani and de Andrade (2003) (World revision, including fossils).

Figs. 33 C, D
This genus can be found in all the Old World tropics except Madagascar. Pseudolasius typhlops Wheeler, 1935b is known only from the Philippines. There are historical speci-mens of a different, unidentified species in the ant collection of the UPLB-MNH, and at least one unidentified species reported by Samson et al. 1997. Other unidentified species were recently collected from other parts of Luzon and from Mindanao Island. These are tiny to small, yellow polymorphic ants. They nest in rotten wood on the ground or underground, where they tend root-feeding coccids. These ants may be collected by sifting leaf litter and soil cores and underground baiting.

Figs. 33 E, F
There are specimens of at least 2 unidentified species from a transect study in Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). There are also unidentified specimens from Mindanao Island. Zettel (2008) recently described Recurvidris nigrans from Negros Island. These small, slender ants have propodeal spines that curve upward and forward. They are ground-dwelling and forage in the leaf litter, and may be collected by sifting leaf litter, underground baiting and pitfall trapping. Keys to species: Bolton (1992), Zettel (2008).

Figs. 34 A, B
(New record). There are specimens of an unidentified species from Dumaguete, Negros Island in the MCZ Ant Collection. This species has a longitudinally striate head and mesosoma, and a postpetiole broadly attached to the gaster. It nests and forages in tunnels under bark. These ants are rare and may be collected by searching under the bark of living trees (DMG, GDA, unpubl. notes). Wheeler (1929c) (Review of genus).

Figs. 34 C, D
There is one specimen, from "Boguio" [=Baguio City, Benguet Province, Luzon Island], of Rhoptromyrmex wroughtonii Forel, 1902a in the MCZ Ant Collection. This species was recently found to be abundant by Joanaviva Caceres-Plopenio during a transect study of an abandoned farm on Mt. Isarog, Camarines Sur, Luzon Island and was also collected by Perry Buenavente from a transect study on Mt. Palali, Nueva Vizcaya, Luzon Island (DMG, unpubl. notes). These small ants share similar morphological features with Tetramorium spp., e.g., a sharp clypeal ridge in front of antennal sockets and a lamella at the tip of the sting, but have a heart-shaped head, a broader, convex clypeus, and a keel-like petiolar venter. They are known to form large, ground-dwelling colonies nesting in rotten logs or in the ground and may be collected by sifting leaf litter and pitfall trapping. Keys to species: Brown (1964) Brown (1958) reports one species from the Philippines, Rhytidoponera araneoides (Le Guillou, 1842). There are specimens of an unidentified species from "San Francisco, Agusan", Mindanao Island, in the MCZ Ant Collection. These hard-bodied ants are superficially similar to Gnamptogenys spp. but have a tooth at the anterolateral edge of the pronotum, and a triangular petiole in lateral view. They are generalist predators or scavengers and nest in the ground under rocks but may also be arboreal, and may be collected by sifting leaf litter, pitfall trapping, beating low vegetation over a white sheet and inspecting tree hollows and dead branches in the canopy.

Figs. 35 A, B
There is one valid species known from the Philippines, Romblonella opaca (F. Smith, 1861). It is a widespread species, having been collected in the far-apart islands of Romblon, Rapu-rapu, and Palawan (DMG, unpubl. notes). This species has a large, bulbous, sessile petiole with a tiny denticle on the lower surface. It seems to be tolerant of human disturbance because the Rapu-rapu specimen was collected on a concrete sidewalk. Ants of this genus are ground-dwelling and may be collected by sifting leaf litter, pitfall trapping, and hand collecting. Keys to species: Bolton (1976) (World revision), Taylor (1991a) (Australian).

Figs. 35 C, D
The unique holotype specimen of Simopone chapmani Taylor, 1966, is deposited in the MCZ Ant Collection. These small ants bear a long barrel-shaped petiole and no tibial spurs on the middle legs. They are often arboreal, and presumed to be predators on other ants, and may be collected by beating low vegetation over a white sheet and examining dead twigs or branches in the canopy.

Figs. 35 E, F
Ants of this genus exhibit two main lifeways: the fire ants live independently in familiar ant mounds while the tiny thief ants nest beside other ants or termites. The species known in the Philippines, Solenopsis geminata, also called fire ants, is a common pest in households and agricultural areas. It is highly polymorphic, with a wide range of sizes between major and minor workers. There are unidentified specimens of Solenopsis subgenus Diplorhoptrum, which are tiny, monomorphic ants, collected by Perry Buenavente from a transect studies on Mt. Palali, Nueva Vizcaya Province, Luzon Island and 2 mountains in Mindanao Island (DMG, unpubl. notes). There are also specimens of an unidentified species from a transect study of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep.). These ants may be collected by sifting leaf litter, pitfall trapping, and hand collecting. Key to species: Trager (1991) (World, geminata-group).

Genus Stigmatomma Roger, 1859
Amblyoponinae: 66 spp., 3 known from PH. Figs. 10 A, B Yoshimura and Fisher (2012) recently revived the status of this genus from synonymy. Philippine ants formerly referable to Amblyopone Erichson, 1842 are now transferred to this genus. These cryptic ants have characteristic elongate mandibles and a denticulate anterior clypeal border. In these ants, the gaster is broadly attached to the petiole. They are found under the bark of logs, in rotten wood, leaf litter, or soil and are known to prey on centipedes and beetle larvae. Key to species (as Amblyopone):

Figs. 36 A, B
There are specimens of an unidentified species from a transect studies of Mt. Isarog, Bicol Region, Luzon Island (Alpert and General in prep., Caceres-Plopenio, unpubl. M.S. thesis). There are also specimens of unidentified species from Eastern Samar Province, Samar Island and Polillo Island. These tiny to small, cryptic ants have spongy lobes at the sides of the propodeum, petiole, and postpetiole. They hunt for soft-bodied arthropod prey, usually Collembola (springtails), and nest in the leaf litter. These ants may be collected by inspecting rotten woody debris and dead leaves that are stuck together for nests before sifting leaf litter. Key to species: Bolton (2000)  The species known from the Philippines include the widespread invasive species, T. melanocephalum (Fabricius, 1793), which commonly invades households in search of sweet food. These small ants have a small, flat petiole and reflexed apex of the gaster, such that only four segments are visible in dorsal view. They may forage in the foliage or on the ground for dead insects but also tend coccids and aphids for honeydew. They nest in just about any available cavity in soil, under stones and bark, in living plants, and houses, and may be collected by sifting leaf litter, beating low vegetation over a white sheet, and baiting with sugar. Shattuck (1999), Fisher and Bolton (2007).

Figs. 36 E, F
The species known from the Philippines include the widespread invasive species, T. albipes (F. Smith, 1861), which is very common in highly disturbed or agricultural areas. These ants also have a small, flat petiole but with five visible gastral segments in dorsal view. It can be difficult to distinguish them from Tapinoma, especially in shrunken or deformed specimens. They are scavengers and forage in the foliage and on the ground. They nest in the soil, in rotten wood, and under bark and rocks. These ants may be collected by sifting leaf litter, pitfall trapping, beating low vegetation over a white sheet, hand collecting, and flipping over rocks and loose bark. Key to species: Bolton (2007) (World revision).

Figs. 37 A, B
The Philippine species include widespread invasive species such as T. lanuginosum Mayr, 1870, which are common in highly disturbed or agricultural areas (Wetterer, 2010). Schlick-Steiner et al. 2006 revived T. manobo (Calilung, 2000) from synonymy. There are specimens of several undescribed species (including a species misidentified as Leptothorax by Samson et al. 1997) from a transect study on Mt. Isarog, Bicol Region, Luzon Island (Alpert and General, in prep.). These small ants have a sharp clypeal ridge in front of the antennal sockets and a lamella at the tip of the sting, but the head is roughly rectangular in shape and with a straight-edged or slightly concave anterior clypeal margin. They are variable in size, sculpture of the cuticle, and color. These ants are generalist predators and scavengers, foraging on the ground, and nest in twigs, rotten wood, under rocks or bark. They may be collected by sifting leaf litter, pitfall trapping, breaking into rotten wood and twigs, and flipping over rocks and loose bark. Keys to species: Bolton (1976Bolton ( , 1977 (Oriental, Indo-Australian), Schlick-Steiner et al. 2006.

Genus Tetraponera F. Smith, 1852
Pseudomyrmicinae: 118 spp., 9 known from PH. Figs. 37 C, D These long and slender arboreal ants have large, somewhat flattened eyes, and a reduced clypeus, such that the antennal sockets are near the front edge of the head. They nest in dead twigs and branches. These ants may be collected by beating low vegetation over a white sheet and inspecting dead twigs and branches in the canopy. Key to species: Ward (2001) (Oriental, Australian).

Genus Tyrannomyrmex Fernandez, 2003
Myrmicinae: 3 sp., 1 known from PH. Putative male alate: Figs. 37 E, F This is a genus that is very rarely collected. The three known species were all described from unique worker specimens. A single male specimen, in the Philippine collection of the Bernice P. Bishop Museum of Hawaii, appears to belong to this genus because its mandible has only the apical and subapical teeth followed by a wide toothless masticatory margin and its curved petiole lacks a distinct node. If confirmed, it will be the first known male specimen of Tyrannomyrmex. These small ants have a curved petiole surmounted by a low node, and strongly-curved mandibles with only two teeth. They likely forage deep in the soil and only occasionally emerge in the leaf litter. These ants may be collected by underground baiting, sifting leaf litter and pitfall trapping. Fernandez (2003), Bolton et al. 2006.

Figs. 38 A, B
These flat and slender ants have a large, keel-like ventral petiolar process. They nest in rotten wood and under rocks and forage in leaf litter. Little is known about their biology. They may be collected by sifting leaf litter, pitfall trapping, breaking into rotten wood and flipping over rocks. Bolton (2003).

Genus Vombisidris Bolton, 1991
Myrmicinae: 16 spp., 2 known from PH. Figs. 38 C, D A recently described species, V, was collected from five locations on three different islands, representing the first record of this genus in the Philippines (Zettel and Sorger, 2010a). They also report at least another species, represented by a dealate queen from yet another location. These small ants are recognizable by a sinuate subocular groove running from the mandibular insertion to the latero-occipital margin of the head. Ants of this genus are arboreal, at least one species (V. humboldticola Zacharias & Rajan, 2004 from southern India) nesting in domatia, which are specialized swollen plant structures for harboring ants. These ants may be collected by beating low vegetation over a white sheet and inspecting domatia of epiphytes. Zettel and Sorger (2010a).

Unnamed genus PH02
Myrmicinae: 1 sp. (?), 1 known from PH. Figs. 39 A, B (New record). There is a single specimen of this undescribed genus in the Philippine collection of the Bernice P. Bishop Museum in Honolulu, Hawaii. The collection was loaned to GDA, who found this unique specimen. The specimen was collected by L.W. Quate from San Francisco, Agusan del Sur in 1959. In Bolton (1994), this specimen keys out to "Undescribed genus" (p. 89) (P. Ward and S. Cover, pers. comm.). The diagnostic characteristic of this genus is the presence of the petiolar spiracle in the node, rather than in the peduncle. No collection information is included with the specimen, however, applying different collecting techniques may discover this species.

Unnamed genus PH03
Myrmicinae: 2 spp., 2 known from PH. Figs. 39 C, D (New record). A good nest series of this undescribed genus was collected by Perry Buenavente in a transect study of Mt. Palali, Nueva Vizcaya Province, Luzon Island. A unique specimen of another species (now lost due to theft, Taylor, pers. comm.) was earlier collected by Bambet Alto from Mt. Isarog. These reddish-orange ants seem to prefer high elevations, having been collected from >1450 masl at both locations. These ants may nest in rotten wood (DMG, unpubl. notes). They are characterized by stemmed mandibles with blunt or rounded denticles and a subsessile petiole with an angle protecting the spiracle. These ants may be collected by breaking into rotten wood, sifting leaf litter and pitfall trapping. In profile, gaster with 4 dorsal segments (tergites), the fifth segment reflexed so that anal pore is ventral, not a termination of gaster (Figs. 36 C, D)  Ocelli present; mandibles long and forceps-like with a triangular flange beneath (Figs. 19 A, B)

Glossary of terms
Abdominal segments -morphologically, segment I of the ant abdomen is the propodeum (see below), followed by the petiole (see below), which is segment II. The postpetiole (see below), when present, is segment III. Otherwise, the first segment of the gaster (see below) is segment III. Acidopore -at the apex of the gaster (see below), a round, somewhat raised, orifice, often fringed with hairs at the tip; diagnostic of ants belonging to subfamily Formicinae. Angle -a triangular, broad-based, tooth-like extension of the cuticle.
Antennal club -describes an antennal funiculus that enlarges apically, to form a distinct club of 2-4 segments. Antennal funiculus -the portion of the antenna distal to the antennal scape; composed of 3-12 segments of varying size. Antennal scape -the elongated basal segment of the antenna. Antennal scrobe -a groove above or below the eye, which accepts the folded antenna. Anterior clypeal margin -the leading edge of the clypeus (see below). Bidentate -armed with 2 teeth (mandibles) or short spines (propodeum). Clavate -refers to hairs that are blunt and club-shaped. Clypeus -the anterior sclerite (see below) of the dorsal head, which consists of narrow lateral portions and a shield-like median portion. Coxa -see Leg segments. Declivity -downward slope, eg. as of the propodeum. Dentate -describes mandibles armed with teeth.
Denticle -a small triangular tooth, much reduced in size. Denticulate -armed with denticles. Edentate -describes mandibles without teeth or denticles on the inner margin. Epigaeic -describes ants that live above ground (compare with hypogaeic). Filiform -describes an antennal funiculus with segments of approximately the same size (compare with antennal club). Frons -the region of the head extending from behind the clypeus, and between the eyes to the posterior margin of the head. Frontal carina -(pl. carinae) thin ridges of cuticle on the front of the head, which may form the dorsal margins of the antennal scrobes (see above). Frontal lobe -projection of the frontal carina (see above), which may partially or completely cover the antennal sockets. Gaster -old name for the third main body division of the ant body. Head -the first main body division of the ant body. Hypogaeic -describes ants that live underground (compare with epigaeic). Labial palps -the segmented sensory appendages attached to the labium, found on the anteroventral surface of the head, with a maximum of four segments. These are the inner pair of palps. Leg segments -Each leg consists of the basal coxa, a small trochanter, a usually long and swollen femur, a tibia, anda 5-segmented tarsus, ending in a pair of tarsal claws. Pro-, meso-, and meta-are prefixes that indicate the leg segment of the particular thoracic segment. Mandibles -anterior appendages of the head, with which the ant manipulates its environment. They are variable in shape, dentition, and function, and extremely important in ant taxonomy. Maxillary palps -the segmented sensory appendages attached to the maxillae, found on the anteroventral surface of the head. With a maximum of six segments, they are usually the longer and larger of the palps and are the outer pair of palps.
Mesosoma -(= alitrunk) the second main body division of the ant body. Morphologi-Sternite -the lower or ventral sclerite (see above) of a segment. Striate -describes sculpturing composed of shallow, parallel grooves or lines. Tergite -the upper or dorsal sclerite (see above) of a segment.