Two new species of Megacanthaspis Takagi (Hemiptera, Sternorrhyncha, Coccoidea, Diaspididae) from China

Abstract Two new species of armored scale, Megacanthaspis hangzhouensis Wei & Feng, sp. n. and Megacanthaspis hainanensis Wei & Feng, sp. n. are described and illustrated from specimens collected from China. A key to adult female of Megacanthaspis species is provided.


Introduction
Scale insects or superfamily Coccoidea are a diverse group of mostly sap-sucking insects, with at least 30 families and around 8000 species (Andersen 2010). The most species rich family of scale insects is Diaspididae, with over 2400 described species (Ben-dov 2012). Armoured scale insects (Diaspididae) are mainly diagnosed by the extreme modification of the adult females, including the complete loss of the legs, the reduction of the antennae to a single segment (Andersen 2010) and the modification of the abdomen into a specialised pygidium for forming the test. The higher classification within the family is uncertain but two of the major subfamilies are the Aspidiotinae and the Diaspidinae.
The genus Megacanthaspis is a small group of scale insects and assigned to the subfamily Diaspidinae, mainly feeding on family Lauraeeae. As presently known, all species were distributed in the Oriental Region and Palearctic region. The localities of Megacanthaspis are mapped on Figure 13.
The genus Megacanthaspis was originally established by Takagi (1961) to accommodate a species from Japan. Takagi (1961) characterized the genus as follows: 'It is particularly characterized by having very prominent, conical, glanduliferous processes along the margin of the abdomen.' These features separate the genus Megacanthaspis from other genera such as Mercetaspis Gomez-Menor, 1927(Takagi 1961. Takagi (1970) reported the species M. litseae collected from Taiwan of China and later he (1981) revised the genus, added two new species from Japan and transferred the species Nanmuaspis phoebia Tang, 1977, collected in China into Megacanthaspis. Recently, two further species of Megacanthaspis were found and are described and illustrated herein, bringing the total number of species in the genus to 7 species. A key to all known species of Megacanthaspis is provided. Moreover, a new host belongs to Poaceae is record.

Materials and methods
Slide-mounted specimens, mounted in Canada balsam using the method discussed by Henderson (2011), were studied.
The morphological terminology used in the descriptions mainly follows that of Takagi (1981) which also has illustrations of most of other species included in the genus. The illustrations were drawn from slide-mounted adult females specimens and depicted with the dorsum on the left and venter on the right. All measurements were given in micrometer (μm) and were made using NIT-Elements D. All specimens are deposited in the Entomological Museum, Northwest A & F University, Yangling, Shaanxi, China (NWAFU).

Checklist of known species of the genus Megacanthaspis Takagi
Megacanthaspis actinodaphnes Takagi, 1961; Japan. Megacanthaspis hangzhouensis sp. n.; China (Hangzhou). Megacanthaspis hainanensis sp. n.; China (Hainan). Takagi, 1981;Nepal. Megacanthaspis leucaspis Takagi, 1981; Japan. Megacanthaspis litseae Takagi, 1970;China (Taiwan). Megacanthaspis phoebia (Tang, 1977); China (Zhejiang). Takagi Antennae each with a long seta and a tubercle. Anterior spiracles each with a group of trilocular pores, some species also with pores near posterior spiracles. Pygidium. Pygidium rounded along posterior margin, with a series of serrate processes or plates, none of which are sclerotized enough to call lobes. In certain species, this processes or plates degenerate or invisible. Marginal gland spines occurring on the abdomen, each associated with 1 or more microducts. Gland tubercles present or absent, if present, near both anterior and posterior spiracles, others occurring submarginally of abdominal segments I-III. Ducts. Dorsal macroducts short, 2-barred, with the orifice surrounded by a sclerotized rim, forming obscure segmental rows in some species. Ventral microducts as large as or smaller than dorsal ducts. Anal opening situated on centre of pygidium. Perivulvar pores quinquelocular, present in an arc, sometimes divided into a median group and two lateral groups.

Key to adult female Megacanthaspis Takagi
Diagnosis. The new species is very close to M. phoebia (Tang, 1977) in having 6 pairs marginal gland spines. But differs in having (character-states on M. phoebia in brackets): (i) 2 pairs of gland spines on abdominal segments V and VI (only single on segments V & VI); (ii) marginal dorsal macroducts absent from apex of pygidium between median gland spines (present); (iii) gland tubercles absent (present).
Diagnosis. The new species is very similar to M. phoebia, but can be distinguished by by having (character-states on M. phoebia in brackets): (i) 5 pairs of marginal gland spines (6 pairs); (ii) a macroduct present medially between the median gland spines (absent).