LEFTOGASTBINAE 



ROBBER FLIES OF THE WORLD 



305 



supraalar bristle present or absent: 1 short, stout post- 

 alar bristle. Scutellar margin with only a fringe of 

 fine, moderately long, upturned pile; disc with fairly 

 long pile. Prescutellar area with dense, subappressed 

 pile somewhat longer than the remainder of the mesono- 

 tum. Pleuron without bristles. The upper half of the 

 mesopleuron, which is unusually large and long, has 

 dense, subappressed pile directed downward. The 

 anterior portion of the mesonotum before the suture 

 is twice as long as the posterior portion. The halves 

 of the lateral metasternum meet in a chitinized plate 

 behind the postcoxa. Prosternum not dissociated. 



Legs: The hind femur is long, quite slender and 

 spindly on the basal third, and near this point rapidly 

 enlarging until on more than the outer half it is more 

 than twice as wide as the basal width or height, present- 

 ing a strongly thickened or swollen appearance. No 

 bristles are present but there is abundant, short, sub- 

 appressed pile above and similar slightly longer pile 

 ventrally. This ventral pile extends from the basal 

 third to the outer fifth. Hind tibia as long as the 

 femur and quite slender throughout ; it is not expanded 

 apically and has minute, scattered, appressed pile and 

 weak, short bristles of which there are 2 ventrally near 

 the middle and a dorsal row of 7 short, pale bristles. 

 The subapex bears 3 rather prominent, pale bristles 

 below. The middle femur is very much shorter, less 

 than half as long as the hind femur. Middle tibia with 

 3 very fine, long, weak ventral bristles. The ventral 

 apical bristles are long and also yellow. Anterior 

 femur without bristles ; this tibia is without bristles or 

 at most has 1 or 2 very minute bristles. Apex with 

 a single, very long, anterior, black bristle and a minute, 

 posterior, pale bristle. Claws long, only slightly 

 curved, sharp and convergent ; pulvilli are absent ; and 

 there is a very minute, short, slender, empodium ap- 

 proximately an eighth as long as the claws. 



"Wings: The wings are slender, the cells narrow. 

 The posterior or medial crossvein lies a considerable 

 distance from the anterior fork of the fourth vein or 

 medius. End veins of the second basal cell fused 

 distally. Anal cell open. The wing is as wide on the 

 basal half as on the distal half, and the alula is absent. 



Abdomen: The abdomen is quite slender and quite 

 cylindrical on the very long second, third, and fourth 

 tergites. First tergite an eleventh as long as the second 

 and laterally with a vertical band of stiff, bristly hairs ; 

 second tergite considerably (at least a fourth) longer 

 than the mesonotum. Eight tergites are visible, the 

 last quite short. Females with the ninth and tenth 

 tergites developed as a rather flat, subtriangular plate 

 extending beyond the eighth. 



Distribution: Palaearctic: Euscelidia bishariensis 

 Efflatoun (1937) ; conopsoides Pallas in Wiedemann 

 (1818) [=pallasii Wiedemann (1818), pubiceps Loew 

 (1871)] 



Ethiopian: Euscelidia discors Speiser (1913) ; lucida 

 Oldroyd (1939) ; rapax "Westwood (1849). 



Genus Lagynogaster Hermann 



Figures 196, 596, 1181, 1182, 1189, 1190, 2063, 2065, 2069, 2072 



Lagynogaster Hermann, Arch. Naturgesch., Berlin, vol. 82, p. 

 12, 1917. Type of genus: Lagynogaster fuliginosa Her- 

 mann, 1917, by original designation. 



Medium size to very large flies, characterized by the 

 quite elongate, slender, third antennal segment with 

 very short style, the apically club-shaped abdomen, the 

 closed and stalked anal cell, the relatively short, upper 

 anterior, intercalary vein nearly the same length as the 

 medial crossvein, and the flock of hairs along the inside 

 margin at the middle of the hind femur. Separated 

 from AmmophUomima Enderlein by the small, dis- 

 sociated prosternum, as well as the short, upper 

 anterior, intercalary vein. Hind tibia with only 

 1 dorsal bristle near the midpoint and 1 dorsal bristle 

 at the apex in contrast to AmmophUomima. Some 

 species are suggestive in appearance of species of 

 bombyliid genus Systropus "Wiedemann. In Lagyno- 

 gaster the empodium, besides being immensely stout, is 

 nearly as long as the claw. Length 15 to 25 mm. 



Head, lateral aspect: The head is short, the face 

 plane or very slightly raised ventrally and chiefly 

 visible because of the recession of the eyes. On the 

 upper half it is plane with the eye. The occiput is 

 short throughout its length with a few scattered, coarse 

 hairs ventrally over the whole medial surface and fine, 

 slender bristles along the middle and dorsal portions. 

 There is a group of 5 or 6 such bristles a little more 

 stout behind each upper eye corner. The proboscis is 

 cylindrical, its length approximately equals the length 

 of the head; the apex is bluntly rounded and bears a 

 few, fine hairs. There are 3 or 4 hairs on each side 

 ventrally just before the middle. The palpus is small, 

 composed of 1 segment but with a distinct trace of the 

 basal segment; the end segment is broadly rounded, 

 clavate, short, with 5 slender bristles arising in the 

 middle of the lateral aspect. The antenna is attached 

 at the upper fourth of the head; it is slender and 

 moderately elongate, the first two segments are short, 

 of equal length ; the first bears 2 setae ventrally at the 

 apex, the second bears 2 small bristles at the apex, and 

 both with setae dorsally. The third segment is slender, 

 widest in the middle, gently attenuate towards base 

 and apex and nearly twice the combined length of the 

 first two segments. It carries a distally thickened 

 style with bristle at tip. This style is generally about 

 two-thirds as long as the third segment. 



Head, anterior aspect: The head is wide and fully 

 as wide as the thorax, the face below the antenna is 

 very narrow, less than a fifteenth the head width and 

 strongly divergent below. Face densely covered with 

 coarse, appressed pubescence, generally without pile 

 and with about 3 pairs of moderately long, stout 

 bristles in 1 row across the epistoma. Front small, 

 slightly widened towards the vertex, micropubescent, 

 without pile; the narrow vertex is moderately exca- 

 vated and has vertical sides. The ocellarium is large, 



