LAPBEIlNiB 



ROBBER FLIES OF THE WORLD 



343 



a pair of slender, long, anterior bristly hairs and 2 

 fine hairs posteriorly. There may be 2 pairs of long, 

 stout, ocellar bristles present, Eye facets centrally 

 enlarged. 



Thorax: The thorax is pollinose. The pile of the 

 mesonotum is rather abundant, short, subappressed 

 and strongly setate. Present are stout, long, lateral, 

 mesonotal bristles consisting of 1 to 7 humeral, with, 

 in the type of genus, a diagonal row of 3 strong, noto- 

 pleural and similar oblique row of 3 others between 

 the notopleuron and the humerus, or with 10 or 11 

 long, stout bristles over the whole notopleural area; 

 also 2 to 4 supraalar, with sometimes 2 additional bris- 

 tles opposite the postalar; 3 to 5 postalar; and 5 or 6 

 pairs of long, stout scutellar bristles on the margin. 

 Other species may have 10 supraalar, 10 postalar, and 

 6 pairs of scutellar bristles. Scutellum moderately 

 thick, pollinose, and convex, with shallow, basal crease 

 and the surface with numerous, short setae or in some 

 cases with rather long, fine pile. In the type of genus 

 acrostical elements are not differentiated, but there are 

 some long, fine, slender bristles on the posterior fourth 

 of the mesonotum and these often become rather stout. 

 Humeral bristles may be completely absent in some 

 species. Propleuron with long, fine, pile ventrally and 

 also, in the type of genus, on the postpropleuron ; 

 pronotum with weak bristles. In others the post- 

 propleuron varies from slender, bristly hairs to as 

 many as 7 or 8 strong bristles. Mesopleuron with a 

 few scattered hairs dorsally, others on the posterior 

 and anterior sternopleuron and again on the posterior 

 hypopleuron. Pteropleuron apilose. Posterior mar- 

 gin of the mesopleuron with 2 to 5 long, stout bristles; 

 metapleuron with a vertical band of long, slender bris- 

 tles; metanotal slopes pubescent only. Lateral meta- 

 sternum pilose, the ventral metasternum wide, chitin- 

 ized, isolated behind and pilose ; the postmetacoxal area 

 membranous ; tegula with bristles. 



Legs : The legs are stout without being swollen ; the 

 pile is dense, rather short appressed and setate on the 

 dorsal surfaces of the femora and tibiae. In the type 

 of genus the following complement of bristles is pres- 

 ent: hind femur with 3 or 4 lateral, 2 strong dorso- 

 lateral, 1 at the middle, 1 at the apical fourth, the latter 

 doubled, and an additional pair at the apex dorsally on 

 each side. Hind tibia rather stout, distinctly arcuate 

 with 3 or 4 stout, dorsomedial bristles, a like number of 

 dorsolateral and 2 stout, lateral bristles, 1 at the basal 

 and 1 at the apical third. In the unique type of 

 genus the middle legs are missing. Anterior femur 

 with 1 strong, ventral bristle near the base, 3 to 5 

 posterodorsal, 2 of them weak, 1 strong anterior at 

 the basal third and 1 anterodorsal at the outer 

 fourth and 2 anterior bristles at the apex. The anterior 

 tibia bears 2 basal anterodorsal, 4 strong posterodorsal, 

 3 stout posterior and 2 or 3 strong, posteroventral 

 bristles. Tibia without spine. Claws long, sharp, 



curved from the base; pulvilli long, thin and wide; em- 

 podium long and bladelike, not or scarcely swollen at 

 the base. In other species the bristles of the middle 

 and anterior legs are even more strongly developed and 

 somewhat more numerous. 



Wings: The marginal cell is closed with a long 

 stalk and is gently sigmoid, ending far above the wing 

 apex; the costa ends above the wing apex and the am- 

 bient vein is completely absent. In the type of genus 

 the first posterior cell is narrow throughout, closed with 

 a long stalk, the fourth posterior cell closed with an 

 extremely long stalk, all the medial and cubital veins 

 evanescent towards the wing margin, the anal cell 

 clossd and stalked, the middle end vein of the second 

 basal cell present but short, the alula only moderately 

 wide but extending considerably outward from the 

 base of the anal lobe. This is the condition of the wing 

 in 10 described and 9 undescribed species. In 1 de- 

 scribed and 2 undescribed species the first posterior 

 cell is widely open. 



Abdomen: The abdomen is robust and as long as or 

 slightly longer than the wings. The first tergite is long, 

 as long as the second medially but short laterally. The 

 pile is coarse, appressed, setate and scanty. Laterally 

 in the middle of each tergite are 2 or 3 quite stout 

 bristles and sometimes slender, bristly hairs, especially 

 on the sides of the first tergite. Males with seven ter- 

 gites, the seventh being a third to half as long as the 

 sixth; females with eight tergites, the last two or three 

 a little narrowed laterally. Male terminalia prominent 

 and partly rotate. The epandrium forms an undivided, 

 only moderately convex, bowllike structure; the true 

 ventral aspect is widely and fully open; the gonopod 

 swollen at the base but separated ventrally. The 

 aedeagus is exposed within the genital cavity and some- 

 times takes strange forms with grotesque terminal 

 plates; bristles are moderately numerous. Female 

 terminalia consist of a very short lappetlike plate 

 protruded beyond the margin in the middle of the 

 eighth tergite; lateral posterior corners of eighth ster- 

 nite with a flat lobelike extension or process. 



Distribution: Neotropical: Nusa cinerea Bellardi 

 (1861); inornata Loew (1851); hucophaea Lynch 

 Arribalzaga (1880). 



Palaearctic: Nusa pueTla Kondani (1873) ; ramicosa 

 Loew (1871); triangulifera Austen (1914). 



Ethiopian: Nusa africana Eicardo (1925) ; albicans 

 Engel (1932) ; brachyptera Loew (1851) [ = stenura 

 Loew (1857)]; dispar Gerstaecker (1871); infumata 

 Loew (1851); fnigrapex Bigot (1878); rufcornis 

 Wulp (1899) ; vittipes Bezzi (1915). 



Oriental: Nusa aequalis "Walker (1851); aJblbasis 

 Eicardo (1927) ; elva Walker (1849) ; formio Walker 

 (1851) ; grisea Hermann (1914) ; yerburyi Eicardo 

 (1927). 



Australian: Nusa queenslandica Eicardo (1918). 



Country unknown: Nusa Jieteroneura Macquart 

 (1S38), (?Arabia, ^Brasilia). 



53591-1 



-62— pt. 1- 



-23 



