﻿Description of three new species and new distributional data for three species of Homalotylus (Hymenoptera, Encyrtidae) from China

﻿Abstract Homalotylustianjinensis Zu, sp. nov., H.bicolor Zu, sp. nov. and H.guangxiensis Zu, sp. nov. are described as new to science; H.agarwali Anis & Hayat, 1998, H.hemipterinus (De Stefani, 1898) and H.varicolorus Krishnachaitanya & Manickavasagam, 2016 are newly recorded from China. A key to Chinese species based on females is also presented.


Introduction
Homalotylus is a well-known genus of Encyrtidae, which was established by Mayr (1876) based on the type species Encyrtus flaminius Dalman.Depending on the classification, this genus is placed either in the tribe Homalotylini, subtribe Homalotylina (Trjapitzin 1989) or the tribe Echthroplexiellini, subtribe Homalotylina (Noyes 2010).The species in this genus are solitary or gregarious larval parasitoids, emerging from the prepupal stage of coccinellids (Coleoptera: Coccinellidae) and feeding on sternorrhyncha hemipterans (Hemiptera: Aphidoidea, Coccoidea, Psylloidea).Records of scale insects as hosts are incorrect and those of other hosts, e.g.Chrysomelidae, Bruchidae or Gelechiidae are also probably erroneous (Noyes 2010).The genus contains 66 valid species (Noyes 2019) and nine species from China (Xu and He 1997;Tan and Zhao 1997).
Contributions to the taxonomy of this genus have been made by several authors, such as Trjapitzin (1989) from the Palaearctic, Anis and Hayat (1998) and Krishnachaitanya et al. (2016) from India, Trjapitzin and Ruíz Cancino (1998) from the New World and Xu and He (1997) from China.In this paper, ZooKeys 1184: 273-289 (2023), DOI: 10.3897/zookeys.1184.113292 Guohao Zu et al.: Three new species of Homalotylus from China we describe three new species and three new Chinese records of Homalotylus from Tianjin and Guangxi, China, and provide a key to the females of the Chinese species.

Materials and methods
All the specimens in the present study were collected from the campuses of Tianjin Agricultural University and Beibu Gulf University by malaise traps, then dissected and mounted in Canada Balsam on slides following the method described by Noyes (1982).Morphological terminology and abbreviations follow those of Noyes (2010) with some modifications.Photographs were taken with a digital CCD camera attached to an Olympus BX51 compound microscope.Body lengths were measured using a Leica M205A stereomicroscope; other measurements are relative and taken from micrometer divisions using the eye piece of a stereozoom microscope for carded specimens and the eye piece of a compound microscope for slide-mounted parts, and then transformed into absolute lengths.The holotype of the new species is deposited in the insect collections of Tianjin Agricultural University, China.
The following abbreviations are used in the text: .Head generally orange yellow, with genae, frontovertex and occiput dark brown.Antennae dark brown, F4 mostly white with lower margin brown, F5, F6 and clava white.Mesosoma dark brown with shallow metallic green sheen, scutellum mostly orange yellow, only with a brown area at base; legs dark brown, except for apical 3/5 of mid tibia, mid tibial spur, mid and hind tarsus 1-4 white.Metasoma dark brown.
Head (Fig. 1) with numerous conspicuous setae on frontovertex, each about as long as diameter of posterior ocellus.Head in front view 1.16× higher than wide.Frontovertex 0.22× head width.Ocelli forming an angle of 33°, posterior ocelli close to eye margin, distance to occipital margin 1.50× the diameter of anterior ocellus.Malar space 0.18× eye height.Antennal torulus with its dorsal margin slightly below lower eye margin and very close to oral margin, and the distance of antennal torulus by 1.95× its own height.Antennal (Fig. 2) scape slender, 8.42× as long as wide; pedicel 2.5× as long as wide, 1.5× as long as F1; all funicle segments longer than wide, F1 1.57× as long as wide, F6 1.11× as long as wide; funicle with linear sensilla on all segments; clava 3-segmented, 3.40× as long as wide, and as long as F4-F6 combined, apex strongly obliquely truncate, truncate part approach to the base of the clava.Measurements Mesosoma (Fig. 3) with sculpture on dorsum similar to that on frontovertex but that on mesoscutum a little shallower; notaular lines conspicuous but not quite meeting at middle of posterior margin of mesoscutum.Mesoscutum 0.72× as long as wide; scutellum 0.94× as long as wide.Fore wing (Fig. 4) 2.65× as long as wide; linea calva interrupted by 4 lines of setae and closed by 5 lines of setae posteriorly; marginal vein 0.44× as long as stigmal vein, and about half the length of postmarginal vein.Hind wing (Fig. 5) 3.73× as long as wide.Length of mid tibial spur (Fig. 6) 0.48× of mid tibia and longer than mid basitarsus.Measurements (μm): FWL, 1325; FWW, 500; SMV, 600; MV, 50; PMV, 100; SV, 113; HWL, 970; HWW, 260; MT, 810; mid tibial spur, 390; mid basitarsus, 360.
Male.Length, 1.67 mm.Color is similar to female, except for F4 completely brown.
Head (Fig. 7) in front view 1.11× higher than wide.Frontovertex 0.23× head width, ocelli forming an angle of about 35°.Malar space 0.17× eye height.Antennal torulus with its dorsal margin slightly below lower eye margin and very close to oral margin.Antennal (Fig. 8) scape slender, about 5.9× as long as wide; pedicel 2.18× as long as wide, 1.40× as long as F1; all funicle segments longer than wide; clava unsegmented, 3.72× as long as wide.
Etymology.The specific name refers to its coloration of mesosoma.
Diagnosis.The new species may be distinguished from H. scutellaris Tan &Zhao, 1997 andH. mundus Gahan, 1920, by the following characters: scape  Description.Female.Holotype.Length, 2.11 mm (excluding ovipositor).Head black, with metallic green luster; antennae dark brown, F3 paler apically, F4, F6 and clava white.Mesosoma dark brown with metallic sheen; basal half of tegula white, apical half dark brown; wings mostly hyaline but fore wing weakly infuscate at base and with a distinct, broad brown fascia across wing extending from parastigma, marginal and stigmal veins, setae distad of this uniform in color; legs dark brown, except for apical 1/2 of mid basitarsus and mid tarsus 2-4 white.Metasoma black brown.

Host. Unknown.
Etymology.The specific name refers to its collecting location.
Diagnosis.The new species may be distinguished from H. albitarsus Gahan, 1910 andH. agarwali Anis &Hayat, 1998, by the following characters: F4 completely white (basal brown and apical white in H. albitarsus), hind tarsus brown Description.Female.Holotype.Length, excluding ovipositor, 2.20 mm.Face yellowish brown, frontovertex dark brown, genae dark brown.Antennae dark brown, F6 from brown to white, clava white.Mesosoma black brown, but axilla yellowish brown, scutellum yellowish with a diamond-shaped brown area at the base; tegula white; wings largely hyaline but fore wing infuscate at base and with a distinct, broad more or less parallel-sided brown fascia across immediately distad of this, otherwise apical setae normal and dark; legs dark brown, except for apical 1/5 of mid tibia, all tibial spurs, mid and hind tarsus 1-4 white.Metasoma black, the protruding part of the ovipositor black brown, with only the base yellowish white.

Male. Unknown.
Host.Unknown.Etymology.The specific name refers to its collecting location.Diagnosis.The new species may be distinguished from H. albiclavatus (Agarwal, 1970) andH. vicinus Silvestri, 1915, by the following characters: scape completely dark brown, 7.60× as long as wide (with a long light-colored strip medially, 8.55× in H. albiclavatus), F6 from brown to white (completely white in H. albiclavatus), scutellum yellowish with a diamond-shaped brown area at the base (yellow in H. albiclavatus); F6 from brown to white (dark in H. vicinus), hind femur dark brown (ventrally pale yellow apically in H. vicinus), hind tarsus 1-4 white (2-4 white in H. vicinus).
Diagnosis.This is the first record from China.