Cydistomyia Enderlein

Goodwin, James T., 2010, New species of Cydistomyia Taylor with notes and collection records for other Tabanidae (Diptera) from New Guinea, Insecta Mundi 2010 (117), pp. 1-22 : 10-13

Key to species of Cydistomyia Enderlein known to occur on New Guinea

The key presented below is a modification of the keys found in Mackerras (1964). It does not include the species now placed in the genus Chasmia , but it includes all of the species groups mentioned by Mackerras (1964) plus his nana group ( Mackerras 1971). The key has been modified as necessary to include the four species described herein plus C. kiamialiensis Goodwin (1999). For those unfamiliar with most published keys to Tabanidae , body length refers to the total length of the body, but not the wings, and index, or frontal index, refers to the height of the frons divided by its width measured just above the subcallus.

1. Subcallus shining yellow; mesonotum covered with dense golden tomentum; wing dark, except for clear marginal zone along wing tip, posterior margin and anal area ................................. 2

— Subcallus normally predominantly pilose (except C. perdita ); mesonotum not covered by dense golden tomentum; wings clear to diffusely infuscated ............................................................. 3

2(1). Pleura dark brown with at most a few yellow hairs; abdomen dark brown dorsally and ventrally .................................................................................................................. C. imitans Oldroyd

— Upper half of pleura concolorous with mesonotum, this same color extending rearward to cross the first abdominal sternite laterally; dense tufts of long yellow hairs anteriorly and posteriorly below wing base ............................................................................. C. kamialiensis Goodwin

3(1). Body length 10-12 mm, brownish-black except for orange-yellow band on upper pleura extending onto mesonotum and a yellow stripe along in-turned lateral parts of tergites 1 and 2 .............. ................................................................................................................... C. bisecta Oldroyd

— Without this combination of thoracic and abdominal markings ................................................ 4

4(3). Body length 14 mm or longer; rather bare, almost uniformly grayish black, with diffusely infuscated wings, no pale pattern on abdominal tergites, and at least antennal plates contrastingly orange .................................................................................................................................................. 5

— Body length 15 mm or less (usually less than 13 mm) smaller, patterned or paler, with wings largely clear; if blackish brown and without abdominal pattern ( C. crepuscularis ), body notably hairy ......................................................................................................................................... 6

5(4). Very large (20-21 mm in body length), with bright orange-yellow antennae, palpi and legs, and no white hairs on pleura .......................................................................... C. barretti Mackerras

— Smaller (14-16 mm in body length), with only antennal plates orange; pleura with anterior and posterior tufts of white hair .......................................................... C. macmillani Mackerras

6(4). Medium sized (9-11 mm in body length), slender, mostly dark body, usually with contrasting pale zone around scutum and scutellum; wing darkened anteriorly; abdomen with pattern of median and lateral triangles or vittae, but inconspicuous or no apical bands on tergites ................... 7

— Size variable, small to medium large (7-15 mm in body length) more robust body with different thoracic and abdominal patterns; if small and slender, color more drab and ornamentation inconspicuous .......................................................................................................................... 11

7(6). Orange-brown body with yellow median and lateral vittae on abdominal tergites ....................... ............................................................................. C. latistriata (Schuurmans Stekhoven)

— Brown to blackbody, with pale median and lateral triangles on abdominal tergites ................. 8

8(7). Distinct yellowish dorsocentral vittae on mesonotum in front of suture ....................................... ....................................................................................................... C. lamellata (de Meijere)

— Mesonotal dorsocentral vittae inconspicuous or absent .............................................................. 9

9(8). Callus small, brown; subcallus, parafacials, face and pleura almost uniformly brown; brown body, with narrow yellowish cream thoracic margins .......................... C. similis Mackerras

— Callus larger, black; subcallus brown, contrasting with cream to white lower parafacials, face and pleura ............................................................................................................................... 10

10(9). Dark brown body (like C. lamellata ), with yellowish cream pattern, including wide zone round scutum and scutellum; antennae and palpi shorter .......................... C. oldroydi Mackerras

— Blackish body, with white pattern, including narrow zone around scutum and scutellum; antennae and palpi longer ...................................................................................... C. laeta (de Meijere)

11(6). Yellow-brown to blackish body, with clearly defined pattern of pale triangles or bands, or both, on the abdominal tergites ............................................................................................................ 12

— Usually more reddish to yellowish, occasionally blackish, unadorned body, without clearly defined abdominal pattern, though there may be paler fringes or vague median vitta on tergites .. 28

12(11). Ornate body, with brown subcallus and black antennae contrasting with pure white parafacials and face and unusually plump, long-haired, generally whitish palpi .................................... 13

— Not such body; palpi slender, darker, short-haired ................................................................... 16

13(12). 11-13 mm in body length, strikingly patterned body, with unusually wide frons (index 2.3-3.0); scutum with conspicuous grayish white dorsocentral vittae and lateral areas grayish broadly merging on each side in front of scutellum; abdomen with large, discrete, grayish white median and lateral triangles on tergites 2-4 or 5 ................................................. C. heydoni Oldroyd

— Less strikingly patterned body, with narrower frons (index 4 or more), less definite scutal pattern, and different abdominal markings ......................................................................................... 14

14(13). Brightly patterned body, usually 8-9 mm I body length, with short callus, moderately narrow frons (index about 4) short antennal style, and grayish white apical bands expanded into median and lateral triangles on abdominal tergites ................................................................................ ................................................................ C. albidosegmentata (Schuurmans Stekhoven)

— Larger body (10 mm or more in body length), with narrower frons (index at least 5) ............. 15

15(14). Darker body, 12 mm in body length, callus elongate and tapering from base to apex; dorsum of thorax and abdomen blackish with pale grayish pattern of median and lateral triangles on tergites; wing with strong appendix at fork ........................................ C. perdita Mackerras

— Paler body, 11 mm in body length, callus dorsally rounded with a slender linear dorsal extension; dorsum of thorax and abdomen brown with grayish pattern of median and lateral triangles on tergites; wing without appendix at fork ............................................... C. missimiensis n. sp.

16(12). 10-12 mm in body length, rotund, black body, with white subcallus and black antennae; scutum with golden to cream notopleural lobes, dorsocentral vittae (variable) and crescents in front of black scutellum; abdominal tergites with small median and lateral golden to cream triangles .......................................................................................................... C. albithorax (Ricardo)

— Not rotund; scutal pattern otherwise ......................................................................................... 17

17 (16). 9-11 mm in body length, black and white body, with black antennae and palpi, white scutellum, large white spot on upper mesopleural convexity, and white pattern on abdominal tergites limited to conspicuous apical bands on 2 and 3 or 2-4 and lateral triangles on 1-4 ................... ..................................................................... C. latisegmentata (Schuurmans Stekhoven)

— Brown or gray body, with less contrasting pattern, and apical bands on most visible tergites 18

18(17). Frons with indefinite or no callus, though there may be thinly tomentose raised area on its lower part ......................................................................................................................................... 19

— Frons with clearly define callus ................................................................................................ 21

19(18). Palpi very short and plump; beard and pleural hairs mainly brown; clearly defined, yellow-haired median triangles on abdominal tergites; yellow-brown, 13-15 mm in body length .................... ............................................................................................................. C. immatura Oldroyd

— Palpi of more normal shape; beard and pleural hairs mainly white; median pale triangles on abdominal tergites shallow, indefinite .................................................................................... 20

20(19). Larger (15 mm in body length), yellow-brown body with narrower frons (index 3.5) ................... ................................................................................................... C. pseudimmatura Oldroyd

— Smaller (11 mm in body length), duller grayish brown body, with wider frons (index 2.8) .......... ................................................................................................ C. quasimmatura Mackerras

21(18). 12 mm in body length, gray body, with black callus, slender antennae, dark palpi, and whitish apical bands but indefinite median triangles on abdominal tergites .......................................... .......................................................................... C. griseiventer (Schuurmans Stekhoven)

— Dark to yellowish brown body ................................................................................................... 22

22(21). 10-12 mm in body length, dark brown body, with black palpi, diffusely paler scutal margin and scutellum, and abdominal tergites with fawn-cream apical bands, but usually an evident median triangle only on tergite 2 ........................................................................................................ 23

— Brighter or duller brown body with brown or cream palpi, more evenly colored mesonotum, and different abdominal pattern .................................................................................................... 24

23(22). Frons diverging slightly from middle to its union with subcallus; callus almost touching eyes basally, wedge-shaped, tapering gradually to a pointed apex that lies just below middle of frons; subcallus grayish pollinose, more or less concolorous with parafacials and face ....................... .................................................................................................................... C. madangi n. sp.

— Frons parallel sided, slender, more than 5 times as high as wide; callus basally taller than wide with a long slender extension that reaches well above middle of frons; subcallus brown, contrasting with grayish white parafacials and face ................................ C. torresi (Ferguson and Hill)

24(22). Normally shaped, brighter brown body, with at most costal cell of wing brown, and clearly defined pattern of apical bands and triangles on abdominal tergites ................................................. 25

— More slender, duller brown body, with wings darkened in radial area, and less definite abdominal pattern .................................................................................................................................... 26

25(24). 13 mm in body length, with pale yellow callus, wide, orange antennal plate, only slightly darkened style, whitish, palpi with black-hair .................................................... C. inopinata Oldroyd — 10-12 mm in body length, with brown callus, more slender, brown antennal plate, deep brown style, and fawn palpi ........................................................................... C. immigrans Oldroyd

26(24). 12 mm in body length, with wide yellow callus, and brown subcallus contrasting with white lower parafacials and face; beard white ........................................................ C. sylvioides (Walker)

— 8-10 mm in body length, with brown callus, and brown parafacials and face almost concolorous with subcallus or subcallus, parafacials and face grayish white ........................................... 27

27(26). Subcallus, parafacials and face brown; frons about 5 times as high as wide; palpi brown ........... .................................................................................................. C. hollandiensis Mackerras

— Subcallus, parafacials and face grayish; frons about 3.5 times as high as wide; palpi grayish .... ............................................................................................................. C. moresbyensis n. sp.

28(11). 12-14 mm in body length, blackish body, with dense covering of dark brown to black hair including beard; legs dark brown to black .................................................... C. crepuscularis Oldroyd

— Brighter red-brown to yellowish or fawn body, less hairy, smoother ........................................ 29

29(28). Robust (mostly 12-15 mm in body length), variable, dark red-brown to orange-yellow, with relatively wide frons and callus, and wings often stained brown .......................... C. lorentzi (Ricardo)

— Usually less than 12 mm in body length or more slender, paler or duller yellow-brown to golden or grayish, with narrower frons, and wings usually darkened only in costal and radial areas 30

30(29). Compact, usually 10-12 mm in body length, light yellow to golden, occasionally grayish body, with moderately narrow, almost parallel frons (index 6), short antennae, and often with median vitta of golden hairs on abdominal tergites ....................... C. sol (Schuurmans Stekhoven)

— More parallel-sided or longer-bodied, yellowish to dull brown body, with longer, more slender antennae ................................................................................................................................. 31

31(30). Longer—bodied (11-13 mm in body length), yellow-brown body, with very narrow, yellowish frons (index more than 6), and yellow hairs on abdominal tergites usually not tending to form definite pattern .................................................................................................................................... 32

— Small to very small (8-10 mm in body length), dull-brown to yellow-brown body with narrower fronts (index less than 6), either abdomen with at least indications of pale apical bands on abdominal segments or vein R 4 with a short appendix .......................................................... 33

32(31). Frons converging, callus oblong, filling frons below, and with short linear extension .................. ................................................................................................................ C. nokensis Oldroyd

— Frons almost parallel, callus usually forming longitudinal ridge on almost its whole length ...... .......................................................................................................... C. solomensis (Ricardo)

33(31). Small (8-10 mm in body length), dull brown body, with brown, moderately narrow frons (index about 5), brown beard, and usually indications of pale apical bands and median triangles on abdominal tergites .................................................................... C. hollandiensis Mackerras

— Very small (8-9 mm in body length), yellowish fawn body, usually without indications of pale apical bands and median triangles on abdominal tergites .................................................... 34

34(33). Frons diverging from vertex to union with subcallus, about 3.5 times as high as wide; callus almost as wide as frons, roughly egg-shaped with larger end toward subcallus, upper end bearing a short pointed extension, entire callus less than half height of frons ....... C. waigani n. sp.

— Frons nearly parallel sided, more than 5 times as high as wide; callus almost touching eyes basally, then tapering rapidly to a slender median line that distinctly extends dorsally beyond middle of frons ................................................................... C. nana Mackerras and Rageau