DASYPOOONINAE 



ROBBER FLIES OF THE WORLD 



155 



with pubescence only. Pleuron micropubescent except 

 on the propleuron which has fine hairs and the prono- 

 tum which has a row of weak bristles. Metapleuron 

 with a band of 12 fine, long hairs. Postmetacoxal 

 area membranous, prosternum fully dissociated. 



Legs : The legs are comparatively elongate, especially 

 the hind pair; they are rather loosely covered with 

 stout, appressed setae. Bristles are greatly reduced, 

 short, very few on the femora, more abundant on the 

 tibiae and more conspicuous on the hind pair. Hind 

 femur slender but distinctly and gradually dilated 

 apically. It bears 6 lateral bristles. On the distal 

 part are 3 medial bristles, and matching the lower ele- 

 ments at the subapex are 1 dorsolateral and 1 dorso- 

 medial bristle. All these distal bristles are longer and 

 stouter. Hind tibia is about as long as femur, quite 

 slender but strongly dilated near the apex. The some- 

 what longer bristles are quite stout; there are present 

 5 dorsolateral, the same number of dorsomedial, and 

 also the same number of ventrolateral bristles. Along 

 the middle there are 4 ventromedial bristles. Apex 

 with 2 dorsal, 2 medial, and 6 ventral bristles. Hind 

 basitarsus moderately long, at least as long as the next 

 three segments, which are comparatively beadlike. 

 Middle femur stout, with a short bristle near the apex 

 in front and behind. The anterior femur has only 

 the posterior bristle. Middle tibia with 3 anterodorsal, 

 3 basal posterodorsal, 5 posteroventral, and 2 long, 

 stout, distal ventral bristles. Anterior tibia rather 

 similar with 6 anterodorsal, 4 posterodorsal, 4 postero- 

 ventral and likewise 2 long, distoventral bristles. 

 Apex without spine. Tarsus similar to the hind pair. 

 Claws stout basally, sharp at the apex, curved at apex. 

 Pulvilli well developed, empodium swollen basally. 



Wings : The wings are uniformly tinged with brown, 

 dark in the anterior marginal cells. Marginal cell 

 widely open, the second vein slightly curved forward 

 at apex. Anterior branch of the third vein gently sin- 

 uous and ending slightly above apex. First posterior 

 cell open maximally. Fourth posterior cell somewhat 

 narrowed. Anal cell widely open. Alula present but 

 reduced. Posterior crossvein absent. Medial cross- 

 vein longer than the upper anterior intercalary vein. 

 The anterior crossvein enters the discal cell beyond the 

 middle. Ambient vein complete. 



Abdomen: The abdomen is elongate and subcylin- 

 droid. The margins of the segments tend to be slightly 

 rolled laterally and slightly flattened. Pile of abdomen 

 consists of sparse, fine, suberect setae. First segment 

 laterally with 2 short bristles and a few hairs. Near 

 the base of the second segment is a distinct, shallow, 

 transverse, concave depression. The third to fifth seg- 

 ments are almost equal in length, the sixth nearly as 

 long. Males with eight segments, the eighth less than 

 , half as long as the seventh ; the seventh is little more 

 than half as long as the sixth. Females with eight 

 segments, the eighth reduced to about half the length 

 of the seventh. Male terminalia comparatively large, 

 rotate one-fourth; the epandrium has a lateral, obtuse, 

 knoblike process on each side with the proctiger be- 



tween. Hypandrium broad and comparatively long. 

 Gonopod prominent, laterally convex with a short proc- 

 ess that curves inward. The cavity is open below. 

 Females with acanthophorites and 5 pairs of somewhat 

 shortened, bluntly rounded spines. 



Distribution: Australian: Neodioctria australis 

 Ricardo (1918). 



Genus Microstylum Macquart 

 Figures 150, 475, 953, 962, 1779, 1786, 2023 



Microstylum Macquart, Dipteres exotiques, vol. 1, pt. 2, p. 26, 

 1838. Type of genus : Dasypogon venosum Wiedemann, 

 1821. Designated by Back, 1909, the first of 10 species. 



Megapollyon Walker, Insecta saundersiana, vol. 1, pt. 2, p. 85, 

 1851. Type of genus : Dasypogon acutirostre Loew, 1852. 

 Designated by Coquillett, 1910, the first of 13 species. 



Megapollion Bigot, Ann. Soc. Ent. France, ser. 3, vol. 5, p. 588, 

 1857, lapsus. 



Microstylum has 2 subgenera, Ep'iblepharis Bezzi and 

 Eclipsis Bezzi. 



Large and sometimes giant flies characterized by the 

 elongate, tapered, obtuse abdomen, and the long wing. 

 The extremely robust species formerly included here are 

 segregated apart on the presence of a mesotibial lobe 

 or spur. Characteristically the species of Microstylum 

 are short, pilose flies with rather slender femora and 

 tibiae ; the bristles are prominent, the thorax pollinose ; 

 the abdomen is rarely wholly pollinose, more commonly 

 shining and sometimes with transverse pollinose fascia. 

 All members of the Microstylum group have bristly or 

 pilose metanotal callosity. The proboscis is unusually 

 long, almost always strongly compressed laterally, 

 sometimes approximately triangular, its apex rather 

 sharply pointed and for a short distance depressed dor- 

 soventrally. These flies are further characterized by 

 a characteristic type of venation in which the base of 

 the second posterior cell is strongly swollen, and in 

 which the end vein of the discal cell and of the closed 

 fourth posterior cell, while slightly undulate or sinu- 

 ous, are in alignment and parallel the wing margin. 

 Length 18 to 57 mm. 



Head, lateral aspect: The face is moderately prom- 

 inent, short beneath the antenna, gradually and slightly 

 increasing in length; it is straight or gently convex, 

 distinctly prominent above the epistomal margin, much 

 of it due to the recession of the eye, but part of it due to 

 a low, sometimes more or less abrupt, ventral extension 

 of the face which may be marked off by a transverse 

 groove. Where grooves are absent there are usually 

 transverse ripples in the pubescence ; there may be as 

 many as three grooves. Again, the face may be nearly 

 straight from antennal to epistomal margin. Eye of 

 moderate length, equally developed above and below, or 

 very slightly narrowed below and gently convex ante- 

 riorly. The occiput is rather short, a little better de- 

 veloped medially but obliterated near the vertex. Pile 

 of occiput dense and rather long and covering the whole 

 surface of the occiput except narrowly along the eye 

 margins ; the upper pile may be almost wholly replaced 



