DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



73 



or seek shelter from the sun's rays ; others are found on 

 the edge of woodland or foliage. 



The group is worldwide, but poorly developed in 

 Australia and southern South America. The majority 

 are from the Palaearctic, Nearctic, or Ethiopian regions. 



While it is possible that a key based on the character 

 of the marginal cell, whether open or closed, may be 

 better for preserving natural relationships, I have 

 adopted the character of the presence or absence of ter- 

 gal bristles. 



KEY TO GENERA OF LAPHYSTINI 



1. Tergal bristles confined to the first tergite or none present . 2 

 At least the first and second tergite and almost always 



tergites 2 to 5 with lateral tergal bristles, usually strong . 15 



2. Marginal cell distinctly open, although the first vein may 



sometimes so closely parallel the costa that its end point 

 is not obvious without close inspection; the second vein 



rarely recurrent or rectangular at apex 3 



Marginal cell narrowly closed and stalked, or closed in the 

 margin; second vein almost always recurrent at apex . 13 



3. First posterior cell open 4 



First posterior cell closed and stalked 10 



4. Male with a short, visible seventh tergite. Both sexes with 



a deep conspicuous, transverse, subbasal groove on the 

 second tergite. Lower face rounded, slightly protuberant, 

 with several slender bristles; 2 to 6 seutellar bristles. 



BohaktiaHuII 



Tergite number not unusual or second tergite without 



transverse groove 5 



5. Third antennal segment strongly attenuate basally, dilate 



subapically. Males with a prominent, inverted, bowllike 

 terminalia. Face more or less gibbous on the lower half or 

 two-thirds. Fourth posterior cell closed and stalked. Both 

 sexes with a shallow, transverse, subbasal groove on tergite 

 two. Such bristles as are present tend to be long and fine, 

 like erect, scattered, wiry pile . Helolaphyctis Hermann 

 Third antennal segment not so constructed 6 



6. Ambient vein absent and posterior veins evanescent toward 



the wing margin Gltphotriclis Hermann 



Ambient vein well developed 7 



7. Face rounded, produced and convex 8 



Face largely plane or slightly concave, either densely or 



thinly pilose. Proboscis longer than the face .... 9 



8. Face longest below the antenna; face of normal width. Eye 



widest below. Microsegment nearly half as long as the 

 third segment; antenna exceptionally long. Base of sec- 

 ond submarginal cell scarcely arched. Fourth posterior 

 cell closed in the margin . . . Hoplotriclis Hermann 

 Face prominent, longest ventrally, of reduced height, strongly 

 rounded. Proboscis not extending beyond the face. 

 Head exceptionally wide, and the face wide, the head 

 width two times the head height. Face, front, and occiput 

 with dense, fine pile. Abdomen broad, flattened, and the 

 margin densely fine pilose. First posterior cell widely 

 open. Fourth posterior cell with a long petiole. 



Hexameritia Speiser 



9. Face short, of little height, and concave, with stout bristles 



below and a few scattered hairs above. 



Gerrolasitjs Hermann 



Face high, moderately produced, nearly plane; face together 



with front and vertex densely long, fine pilose; stout 



bristles everywhere absent Triclis Loew 



10. Hind femur exceptionally stout and bearing stout, tubercu- 



late, spinous bristles. Pile of mesonotum and abdomen 

 largely flat appressed, coarse, matted and glittering. 

 Scutellum without bristles, the ambient vein complete. 

 Flies which have the abdomen unusually robust and short 



oval Triclioscelis Roeder 



Hind femur not exceptionally stout 11 



11. Face short and not at all produced. Ambient vein ends at 



anal cell. Short, appressed, pilose flies; first tergite with 



bristles Scttomedes Hermann 



Rather long, densely pilose flies; face distinctly gibbous 

 below 12 



12. Proboscis large, prominent, much longer than face. Face 



prominent and produced on lower two-thirds with sharp 

 ledge above. Pile of face, front and vertex, thorax and 

 scutellum long and dense. Ocellarium with numerous, 

 stiff hairs only. Palpus long and slender. Male with a 

 short, visible seventh tergite. Terminalia inverted; 

 superior forceps complete (Stenopogonini). 



Dioctobroma, new genus 

 Proboscis small, no longer than the face; palpus small. 

 Face moderately produced, beginning below the antenna, 

 and rounded; pile moderately abundant and shorter in 

 character. Third antennal segment attenuate basally. 

 Male with 6 tergites only Zabrops Hull 



13. First posterior cell widely open; lower half of face strongly 



produced and gibbous and bristly. Third antennal seg- 

 ment strongly attenuate basally with a very short, semi- 

 fused microsegment Apoxyria Schiner 



First posterior cell closed and stalked; third antennal seg- 

 ment with 1 or with 2 distinct microsegments .... 14 



14. Antenna slender, elongate; third segment long, cylindroid, 



with 2 microsegments, the second microsegment long and 

 spoon-shaped with enclosed spine. Ambient vein complete. 



Acrochordomerus Hermann 

 Antenna with third segment stout, attenuate near apex, 

 with a single, short microsegment enclosing centrally 

 an apical spine. Proboscis pointed, quite robust at base 

 and extending well beyond the face. Face pile and 

 mystax tectiform. Ambient vein depauperate. 



Saucropogon, new genus 

 15._ Hind femur exceptionally stout and enlarged. Large, robust, 

 flies with dense, flat-appressed, glittering, matted conspicu- 

 ous, abdominal pile; no seutellar bristles. Tergal bristles 

 confined to first, or first and second segments. 



Triclioscelis Roeder 

 Femur of only normal width. Pile, if appressed, is shorter, 

 less conspicuous. Seutellar bristles sometimes present; al- 

 ways with tergal bristles on second to fifth segments . . 16 



16. Marginal cell open 17 



Marginal cell closed, or closed in the margin 21 



17. Stout seutellar bristles present 17a 



Stout seutellar bristles absent ; only stiff hairs or micro- 

 pubescence present 19 



17a. First posterior cell closed .... Ntximyia, new genus 

 First posterior cell open 18 



18. Second vein recurrent at apex. Pile of thorax exception- 



ally short and appressed. Pulvilli reduced to mere stubs. 

 Flies presenting a rather bare, denuded appearance. 



Macahyba Carrera 

 Second vein not recurrent at apex. Marginal cell widely 



open. Pulvilli well developed 18a 



18a. Third antennal segment longer than the combined length 

 of the short beadlike second segment and long first 

 segment. The third segment tapered and reduced in 

 thickness on the outer half. Terminalia characteristic; 

 the epandrium bears laterally long, thin, centrally con- 

 vex, uneven, posteriorly rounded, transparent, wing- 

 like processes, leaving a deep recess, which is notched. 



Laphygmolestes, new genus 

 Third antennal segment usually rather short and always 

 swollen and dilated, so as to be wider than the basal seg- 

 ments. Male terminalia with a short, rotate, incon- 

 spicuous bowl-like epandrium . . . Psilocueus Loew 



