Five new species of Homalotylus Mayr (Hymenoptera: Encyrtidae) − from India with a key to Indian species

ABSTRACT Five new species of Homalotylus Mayr (Hymenoptera: Encyrtidae) – H. noyesi sp. nov., H. biharensis sp. nov., H. varicolorus sp. nov. (from Bihar province), H. montanus sp. nov. (from Tamil Nadu province) and H. insularis sp. nov. (from Andaman and Nicobar Island) – are described from India. A revised key to the Indian species of Homalotylus is provided. http://zoobank.org/urn:lsid:zoobank.org:pub:9209CC16-7A20-49BF-B4C6-95EF0F5567DF


Introduction
Homalotylus was erected by Mayr (1876) for Encyrtus flaminius Dalman. This genus belongs to the subfamily Encyrtinae and the tribe Echthroplexiellini, and has six other synonyms (Noyes 2010). Homalotylus species are generally primary parasitoids of larvae of lady bird beetles (Coleoptera: Coccinellidae) and more rarely parasitise Chrysomelidae (Domenichini 1957;Klausnitzer 1976). However, Trjapitzin (2011) mentioned that the report of Walker (1838) rearing H. flaminius from the pupa of Galeruca calmariensis Walker (Coleoptera: Chrysomelidae) in England needed to be confirmed. Further, he reported that 30 species were reared from grubs and pupae of ladybirds. Anis and Hayat (1998) added that the hosts of Homalotylus are definitely lady bird beetles, and host records of mealy bugs and aphids are undoubtedly erroneous and indicate that the real hosts, which normally live among these hemipterous pests, are overlooked. Sixty-four species of Homalotylus have been described globally (Noyes 2015). Currently, 24 species are known from the Oriental region (Xu and He 1997;Noyes 2015). From India, Anis and Hayat (1998) last described two new species, H. agarwali Anis and Hayat and H. formosus Anis and Hayat, and provided a key to 12 known Indian species.
In this paper, we describe five new species of Homalotylus from Tamil Nadu, Bihar and Andaman Nicobar Island, India, and provide a revised key to the Indian species.

Methods
The length of whole specimens is in millimetres. All other measurements were taken from a micrometer directly fitted into the eyepiece of a Leica S8 APO stereozoom trinocular microscope at 80× (one micrometer division = 0.0125 mm) for card-mounted specimens, or at 100× (one micrometer division = 0.01 mm) using a Leica DM750 phase contrast microscope for slide-mounted parts. Images of card-mounted specimens were captured using a Leica M205C stereozoom trinocular microscope with a DMC2900 camera, and those of slide-mounted parts using a DFC295 camera attached to a Leica DM750 phase contrast microscope.

Diagnosis
Female body relatively large, measuring 0.9 − 2.3 mm in length, body dark brown to fully black or orange-yellow to brown; some dark species with metallic lustre. Head with frontovertex evenly curved and gradually merging with face; ocellar triangle with apical angle acute or 90°; posterior ocelli very close to eye margins; antennal torulus separated from mouth margin by about one-third its own length; eye kidney shaped, dorsally elongate, nearly reaching occipital margin; malar space short, not longer than eye width and generally with a weak malar sulcus. Mandible 3-dentate, rarely with only 2 teeth; maxillary palp 4-segmented, labial palp 3-segmented. Antennal funicle 6-segmented; clava solid or 3-segmented with oblique truncation. Thorax slightly convex; pronotum entire; mesoscutum with complete notaular lines; mid tibial spur frequently conspicuously serrate, varying from a little shorter to distinctly longer than mid basitarsus; basitarsus usually with only line of ventral pegs, rarely with up to 2 rows; hind tibia not broadened and flattened or hardly so, varying from 6-10× as long as broad. Fore wing with marginal vein quadrate to slightly longer than broad; post-marginal vein length variable; stigmal vein long; centre of disc densely and finely infuscate with brown setae, about basal third and apical third with transparent setae. Mesopleuron clearly separated from gaster by propodeum which broadly touches hind coxa; side of propodeum with dense setae, these often slightly flattened, scale-like and silvery. Gaster with anterior margins of T2-T6 medially incised and with a median, longitudinal membranous strip, that on T5 and T6 are rarely incomplete; syntergum broadly shallowly concave without median incision or median membranous strip; syntergum very short, moderately to strongly transverse, 1.8-4.6× as broad as long, usually with a broad apical, semicircular invagination giving it a truncate appearance, rarely apically rounded; sternites II-V of gaster generally with a median membranous strip; hypopygium reaching apex of gaster, anterior margin concave with a median projection, posterior margin varying from virtually straight to acute, with a shallow median invagination; ovipositor varying from not exserted to strongly exserted; outer plate of ovipositor triangular, about 3-4× as long as broad, with up to 8 subapical setae; ovipositor varying from about two-thirds as long as mid tibia to more than twice as long; second valvifer usually without any subapical setae, but with up to 2 when present; gonostylus free, from less than one-tenth as long as mid tibia to about as long (modified from Anis and Hayat 1998;Noyes 2010).
Male. Sexual dimorphism very little. It is difficult to differentiate the sexes in species with a non-exserted ovipositor. Antennal scape in some species with a concavity on dorsal surface. T7 of gaster relatively longer, cercal plates situated at about distal third of gaster. External genitalia with a tubular phallobase, with aedeagal apodemes contained within the phallobase; parameres absent or reduced; digiti well developed, each digitus usually with three denticles (Anis and Hayat 1998).

Comments
Homalotylus can be differentiated from other encyrtid genera using the keys given by Tachikawa (1963) for Japan, Noyes and Hayat (1984) for the Indo-Pacific region, Hayat (1985Hayat ( , 2006 for India and the adjacent countries, and Trjapitzin (1989) for Palaearctic region.

Male
Unknown.

Host
Unknown.

Comments
This species is similar to H. sinensis in having the ovipositor slightly to not exserted, whole antennal funicle black and pedicel at most 2.3× as long as wide, but differs in having ovipositor length, 2 mm; clava 3-segmented; scape 8.75× as long as wide; mid tibia 2.85× as long as mid basitarsus (ovipositor length, 1.8 mm; clava solid; scape 7.5× as long as wide; mid tibia 1.1× as long as mid basitarsus in H. sinensis).

Etymology
This species is named after the type locality, Bihar.

Host
Unknown.

Comments
This species is similar to H. scymnivorus in having the ovipositor exserted and female body dark brown or black, but differs in having ovipositor more than 3× as long as mid basitarsus, scape 8.75× as long as wide; F1-F3 dark brown, F4 light brown, F5 white, F6 and clava orange (ovipositor less than 3× as long as mid basitarsus, scape 7.3× as long as wide; antenna black, shiny, F5, F6 and clava white in H. scymnivorus).

Etymology
The species epithet is a Latin adjective in reference to its island type locality Homalotylus montanus Krishnachaitanya and Manickavasagam, sp. nov. (Figure 3)

Host
Unknown.

Male
Unknown.

Comments
This species is similar to H. agarwali in having the ovipositor exserted, antennal scape less than 8× as long as wide, not constricted at middle, and hind tarsus dark brown, but differs from it in having ovipositor 2× as long as mid tibia; pedicel 2.4× as long as wide; F1-F3 dark black; F4 dorsally white, ventrally light brown; F5-F6 and clava white; (ovipositor 1.03× as long as mid tibia; pedicel 2.16× as long as wide; F1 dark brown, F2 dark brown but paler than F1; F3-F6 and clava white in H. agarwali).

Etymology
The species name is a Latin adjective in reference to the hilly terrain of the type locality.

Comments
This species is similar to H. noyesi in having the ovipositor exserted, scape 7× as long as broad and F1-F4 light brown, F6 and clava white, but differs from it as given below: ovipositor 2.2× as long as mid tibia; pedicel 2.75× as long as wide; fore wing 3.2× as long as wide; clava 3.3× as long as wide; head frontally 1.05× as long as wide; (ovipositor 1.5× as long as mid tibia; pedicel 2.25× as long as wide; fore wing 2.8× as long as wide; clava length 2.7× as long as wide; head frontally 0.92× as long as wide in H. noyesi).

Etymology
The species epithet is a Latin noun in reference to the numerous colours on the body.

Host
Unknown.

Male
Unknown.

Comments
This species is similar to H. varicolorus in having the ovipositor exserted, scape 7× as long as broad and F1-F4 light brown, and F6 and clava white, but differs in the following characters: ovipositor 1.5× as long as mid tibia; pedicel 2.25× as long as wide; fore wing 2.8× as long as wide; clava length 2.7× as long as wide; head frontally 0.9× as long as wide; stigmal vein 1.5× as long as postmarginal vein (ovipositor 2.2× as long as mid tibia; pedicel 2.75× as long as wide; fore wing 3× as long as wide; clava 3.3× as long as wide; head frontally 1× as long as wide; stigmal vein 1.8× as long as post marginal vein in H. varicolorus).

Etymology
This species is named after the encyrtid specialist Dr. John. S. Noyes of the NHM, London.