Three new Cryptochetum Rondani, 1875 (Diptera: Cryptochetidae) from Yunnan Province, China and an identification key to Chinese species

Three species of the genus Cryptochetum Rondani, 1875 from China are described and figured as new to science: C. euthyiproboscise sp. nov., C. glochidiatusum sp. nov., and C. longilingum sp. nov. An identification key to the known species of Cryptochetum from China is presented. The type specimens of the new species are deposited in the Henan Agricultural University.


Introduction
from China are described as new to science. An identification key to the known species of Cryptochetum occurring in China is presented.

Material and methods
Terminalia preparations were made by removing and macerating the apical portion of the abdomen in glacial acetic acid, then rinsed in distilled water before being stored in glycerine-filled microvials. After examination, they were transferred to fresh glycerine and stored in a microvial on the pin below the specimen or moved to an ethanol tube together with the wet specimens. Specimens examined are deposited in the Entomological Museum of Henan Agricultural University (EMHAU), Zhengzhou. The general terminology follows Cumming & Wood (2017).

Results
The genus Cryptochetum is now represented by 18 species from China and an identification key to species is provided below. dm-m crossvein slightly curved (Fig. 30)  16. Apex angle of ocellar triangle slightly wider than distance between antennae; body slightly smaller (body length 1.5 mm) (Fig. 33)    17. Apical angle of ocellar triangle slightly wider than distance between antennae; antennal postpedicel acute apically (Fig. 35)

Diagnosis
Ocellar triangle approximately in isosceles triangle, apical angle shorter than the distance between antennae. Surstylus slightly narrowed and sharp apically.

Etymology
The species epithet refers to the straight palpus. Head. Darkish brown (Fig. 1); ocellar triangle shiny brown with metallic luster (Fig. 2), approximately in isosceles triangle, apex slightly flat; lunule strap-shaped, very narrow, brown. Eye red, bare, 1.8 × as high as long, gena approximately ⅛ of eye height. Setae and setulae on head black; ocelli darkish yellow, placed close together. Ocellar triangle with short setulae, punctures at bases of setulae conspicuous; frons without setae, orbital setae lacking; postvertical setae erect, considerably stouter and longer than other setulae on vertex. Antenna brown with microtomentum, large, same length as face; scape and pedicel with black setulae at middle and margin; postpedicel with pubescence, irregularly rectangular, front margin straight, apical margin curved, 0.5 mm long, 0.2 mm wide, apical angle with stout conical tubercle, a little longer than surrounding setulae. Proboscis flat and straight, brown, with short sparse black setulae, labellum slightly wide. Palpus short, ca 0.2 mm long, apically rounded, darkish brown with short dense black pubescence, margin with short sparse setulae.
THorax. Shiny, darkish brown with brownish stripes and metallic blue-green luster; scutellum shiny, blackish brown. Setae and setulae on thorax black, punctures at bases of setulae deep and numerous; scutellum large, approximately triangular, wide and rounded apically, 0.5 × as long as thorax. Apical setae longer and stouter than other setae. Anepisternum brown with setulae, katepisterunum and anepimeron brownish, bare. Legs slender, blackish brown except tarsi yellowish. Setae and setulae on legs black. Wing hyaline with greenish and purplish reflections, unspotted, 2.3 × as long as wide; veins brown; costal vein (C) extending to end of R 4+5 and terminating at apex of wing; subcostal vein (Sc) weak, slightly angulated; R 1 curved, not angulated, R 2+3 and R 4+5 parallel for 4/ 5 along their lengths, then diverging to wing margin; r-m short; M 1 between r-m and dm-m 1.5 × as long as dm-m, dm-m slightly sinuous, forming an angle nearly at 90° with M 4 , distal portion of M 4 (the part beyond dm-m) 1.9 × as long as dm-m (Fig. 3). Calypter brownish, with brownish microtrichae, margin with brownish setulae. Knob of haltere dark brown, stalk brown.

Female
Unknown.

Remarks
This new species is somewhat similar to C. kunmingense , but may be separated from it by M 1 between r-m and dm-m 1.6 × as long as dm-m; distal potion of M 4 (the part beyond dm-m) 1.9 × as long as dm-m. In C. kunmingense, M 1 between r-m and dm-m 1.2 × as long as dm-m; distal potion of M 4 (the part beyond dm-m) 1.4 × as long as dm-m .

Diagnosis
Ocellar triangle approximately in equilateral triangle, apical angle slightly wider than the distance between antennae. Surstylus extremely narrowed and blunt apically.

Etymology
The species epithet refers to the shape of epandrium, which is spheroid in dorsal view.
Head. Black (Fig. 8); ocellar triangle shiny black with metallic luster (Fig. 9), approximately in equilateral triangle, apex slightly flat; lunule strap-shaped, very narrowed, sooty black. Eye darkish red, bare, 1.8 × as high as long, gena approximately one fourteenth of eye height. Setae and setulae on head black; ocelli darkish yellow, placed close together. Ocellar triangle with short setulae, punctures at bases of setulae conspicuous; frons without setae, orbital setae lacking; postvertical setae erect, considerably stouter and longer than other setulae on vertex. Antenna darkish brown with microtomentum, large, shorter than face; scape and pedicel with black setulae at middle and margin; postpedicel with pubescence, irregularly rectangular, front margin straight, apical margin curved, 0.4 mm long, 0.2 mm wide, apical angle with stout conical tubercle, nearly as long as surrounding setulae. Proboscis flat and short, brownish yellow, with short sparse black setulae, labellum slightly wide. Palpus very short, apically enlarged and rounded, dark brown with short dense black pubescence, margin with short sparse setulae.
THorax. Shiny, blackish brown with metallic blue-green luster; scutellum shiny, blackish brown. Setae and setulae on thorax black, punctures at bases of setulae deep and numerous; scutellum large, approximately triangular, wide and rounded apically, 0.5 × as long as thorax. Apical setae longer and stouter than other setae. Anepisternum darkish brown with setulae, katepisterunum and anepimeron brown, bare. Legs slender, blackish brown except tarsi darkish yellow. Setae and setulae on legs black. Wing hyaline with greenish and purplish reflections, unspotted, slightly 1.8 × as long as wide; veins brown; costa vein (C) extending to end of R 4+5 and terminating before apex of wing; subcostal vein (Sc) weak, not angulate; R 1 curved, not angulate, R 2+3 and R 4+5 parallel for 4/ 5 along their lengths, then diverging to wing margin; r-m short; M 1 between r-m and dm-m 1.2 × as long as dm-m, dm-m slightly straight, not sinuous, forming an angle at 90° with M 4 , distal portion of M 4 ( the part beyond dm-m) 1.8 × as long as dm-m (Fig. 10). Calypter brownish, with brownish microtrichae, margin with brownish setulae. Knob of haltere blackish brown, stalk brownish.

Female
Unknown.

Remarks
This new species differs from other species of Cryptochetum as follows: the antenna is far away from the ocellar triangle, the postpedicel is irregularly rectangular; the epandrium is nearly circular and the cercus is rather narrowed.

Diagnosis
Ocellar triangle approximately in isosceles triangle, apical angle shorter than the distance between antennae. Surstylus slightly narrowed and blunt apically.

Etymology
The species epithet refers to the long proboscis. Head. Black (Fig. 15); ocellar triangle shiny black with metallic luster (Fig. 16), approximately in isosceles triangle, apex slightly flat; lunule strap-shaped, very narrow, sooty black. Eye darkish red, bare, 1.9 × as high as long, gena approximately 1/ 9 of eye height. Setae and setulae on head black; ocelli darkish yellow, placed close together. Ocellar triangle with short setulae, punctures at bases of setulae conspicuous; frons without setae, orbital setae lacking; postvertical setae erect, considerably stouter and longer than other setulae on vertex. Antenna darkish brown with microtomentum, large, shorter than face; scape and pedicel with black setulae at middle and margin; postpedicel with pubescence, irregularly rectangular, front margin straight, apical margin obtuse, 0.6 mm long, 0.3 mm wide, apical angle with stout conical tubercle, nearly as long as surrounding setulae. Proboscis flat and long, brownish yellow, with short sparse black setulae, labellum slightly wide. Palpus short, apically enlarged and rounded, dark brown with short dense black pubescence, margin with short sparse setulae.
THorax. Shiny, blackish brown with metallic blue-green luster; scutellum shiny, blackish brown. Setae and setulae on thorax black, punctures at bases of setulae deep and numerous; scutellum large, approximately triangular, wide and rounded apically, 0.6 × as long as thorax. Apical setae longer and stouter than other setae. Anepisternum darkish brown with setulae; katepisternum and anepimeron brown, bare. Legs slender, blackish brown except tarsi darkish yellow. Setae and setulae on legs black. Wing hyaline with greenish and purplish reflections, unspotted, slightly 1.5 × as long as wide; veins brown; costal vein (C) extending to end of R 4+5 and terminating before apex of wing; subcostal vein (Sc) weak, slightly angulated; R 1 curved, not angulated, R 2+3 and R 4+5 parallel for 4/ 5 along their lengths, then diverging to wing margin; r-m short; M 1 between r-m and dm-m 1.5 × as long as dm-m, dm-m slightly sinuous, forming an angle nearly at 90° with M 4 , distal portion of M 4 ( the part beyond dm-m) 1.5 × as long as dm-m (Fig. 17). Calypter brownish, with brownish microtrichae, margin with brownish setulae. Knob of haltere darkish yellow, stalk brownish.

Female
Unknown.

Remarks
This new species is somewhat similar to C. sinicum Yang & Yang, but may be separated from it by M 1 between r-m and dm-m 1.2 × as long as dm-m, ocellar triangle approximately in isosceles triangle. In C. sinicum, M 1 between r-m and dm-m 1.7 × as long as dm-m, ocellar triangle approximately in equilateral triangle .

Discussion
The Cryptochetidae is the smallest family in the superfamily Carnoidea. Although the life-habits of cryptochetid flies are rather well known, species are hard to collect. In some places, cryptochetids fly around the human head or eyes. The three new species -C. euthyiproboscise sp. nov., C. glochidiatusum sp. nov. and C. longilingum sp. nov. -described in the present paper have some obviously different morphological characters. There are 43 known species of Cryptochetum in the world, ten species are  . 23. C. deltatum . 24. C. tianmuense Yang & Yang, 2001. 25. C. acutulum . 26. C. zalatilabium Xi & Yang, 2015. 27. C. kunmingense . 28. C. fanjingshanum Yang & Yang, 1988. 29. C. maolanum . Scale bar = 0.1 mm known in the Palearctic Region (Rondani 1875;Hendel 1933;Cadahia 1984;Nartshuk 1984;Papp et al. 2018) and until now, 15 species were known to occur in China. Five species of Cryptochetidae have been recorded from Yunnan Province Xi & Yang 2015). Yunnan is one of the world's well-known regions for extremely rich biodiversity, which reveals the potential cryptochetid speciesrich areas in China. The Chinese fauna of Cryptochetidae is extraordinarily rich, with the continued discovery and description of further species.