DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



27 



6. Face unusually wide; the front and vertex, beginning opposite 



the antenna, are greatly expanded and divergent; apex 

 of third antennal segment and apex of first mierosegment 

 without deep, conspicuous clefts. 



Heemannella, new genus 

 Face approximately one-third of the head width or less; 

 beginning below, the face is slightly convergent and this 

 convergence continued at the same rate to the vertex. 

 Apex of third antennal segment and first mierosegment 

 with deep clefts in which is received the attachment of the 

 next succeeding segment Myelaphus Bigot 



7. Fourth posterior cell closed and stalked 8 



Fourth posterior cell widely open 9 



8. Head in frontal aspect as high as wide and therefore nearly 



circular; face narrow and its width not more than one- 

 seventh the head width; third antennal segment slender; 

 face nowhere prominent and only slightly produced below; 



anal cell open 8a 



Head in frontal aspect wider than high; face little less than 

 one-fourth the head width; third antennal segment much 

 swollen and dilated. Anal cell closed and stalked. 



Pritchahdia Stuardo 

 8a. Disc of scutellum bare, or with 1 or 2 minute hairs. Fe- 

 male terminalia enclosed by a cylindroid jacket with wide 

 terminal orifices. Male terminalia rotate, bearing a long, 

 medial (dorsal), stout prong from the hypandrium. 



Aplestobroma Hull 

 Disc of scutellum with long, bushy pile. Female unknown. 

 Male terminalia rather similar to Aplestobroma Hull. 



Pegolabrus, new genus 



9. Head wider than high. Front and antennal base more or 



less swollen, leaving the face usually concave, more rarely 

 a little convex. Third antennal segment often with 



bristles {Dioctria Meigen sensu lato) 10 



Head circular, no wider than high. Face exceptionally 

 narrow, one-tenth of head width and divergent below. 

 Face pile exceptionally long and straight and stiff and 

 confined to a narrow, medial row. Fourth posterior cell 

 widely open; male with terminalia similar to Aplestobroma 

 Hull, the dorsal (inverted) prong much wider. Female 

 unknown Broticosia Hull 



10. Third antennal segment bearing 2 long microsegments, 



together nearly as long as the third segment and with 

 apical spine. Male terminalia large, obtuse, clublike. 

 Hind metatarsus swollen . . Nerterhaptomentjs Hardy 

 Third antennal segment with a single, obtuse, spoon-shaped 

 mierosegment and enclosed spine. Male terminalia short, 

 inconspicuous 11 



11. Hind tibia slender, elongate and with the apical part en- 



larged; hind metatarsus enlarged, elongate, or both, and 

 longer than second and fourth segments together. Scutel- 

 lum more or less convex and bearing short, recumbent, 

 discal and marginal pile. Anterior branch of third vein 

 reaching wing margin at or below the apex of the wing. 

 Wings elongate, narrow, with the axillary cell and alula 



greatly reduced in size 12 



Hind tibia normal, in some species slightly narrowed on the 

 basal half; hind metatarsus normal and subequal in length 

 to second and fourth segments together. Scutellum more 

 or less flattened, bare on the disc, with long, erect, mar- 

 ginal hairs. Anterior branch of third vein reaching 

 anterior margin before the apex of the wing. Wings 

 normal or very broad, the axillary cell and alula well 

 developed 13 



12. First antennal segment longer than the second, third of 



uniform width and the st3'le about equal in diameter to 

 the third segment. Face concave, the oral margin and 

 antennal base more or less prominent . Dioctria Meigen 

 First and second antennal segments nearly equal in length, 

 third narrow basally and quite broad in the middle, the 

 style minute. Face in profile slightly convex, the oral 

 margin and the antennal base not at all prominent 

 (subgenus of Dioctria Meigen). 



Nannodioctria Wilcox and Martin 



13. Scutellum bare of pile. Hind femur and tibia and usually 



the middle and anterior ones with numerous, small, 

 setigerous tubercles below (subgenus of Dioctria Meigen). 

 Eudioctria Wilcox and Martin 

 Scutellum with quite numerous, long, erect, marginal hairs. 

 Femur and tibia without setigerous tubercles (subgenus of 

 Dioctria Meigen) . . Metadioctria Wilcox and Martin 



Genus Dioctria Meigen 



Figures 2, 9, 397, 403, 802, 811. 1633, 1634, 1SS5 1936, 1963, 



2020 



Dioctria Meigen, Mag. Insektenkunde, vol. 2, p. 270, 1803. Type 



of genus: Asilus oelandicus Linne\ 1758. Designated by 



Latreille (1810) the first of 3 species. 

 Methylla Hansen, Naturh. Tidsskr., ser. 3, vol. 14, pp. 145, 198, 



1883. Type of genus: Dioctria humeralis Zeller, 1840, by 



original designation. 



Dioctria has 3 subgenera, Eudioctria Wilcox and 

 Martin, Metadioctria Wilcox and Martin, Nannodioc- 

 tria Wilcox and Martin. 



Small or medium size flies, characterized by the elon- 

 gate, comparatively slender abdomen, in the female 

 without spines or acanthophorites on the ninth tergite ; 

 male terminalia not rotate and epandrium without for- 

 ceps. The abdomen is sometimes slightly clavate and 

 tends to be corrugate on the dorsal aspect of the basal 

 segments. Face almost plane, or slightly bulbous be- 

 low, or with only the middle portion plane. Face, ex- 

 cept in a few instances, characteristically protuberant 

 at and just below the base of the antenna. Antenna at- 

 tached usually near the vertex; the front, therefore, 

 short; antenna elongate, slender, with apical, spoon- 



shaped mierosegment enclosing a spine. All cells of the 

 wing open, usually widely open. Length 8 to 20 mm. 

 Head, lateral aspect : Face plane, level with the eye in 

 the middle of the face, gently rounded and slightly pro- 

 tuberant on the lower third and rather strongly pro- 

 tuberant on the upper third. Occiput short, a little 

 more prominent below, becoming a little thicker towards 

 the middle of the head; pile stiff and bristles moder- 

 ately abundant below ; stout bristles begin at the lower 

 third, curve slightly forward and consist of 25 or more 

 pairs, some of which are rather strongly curved. Pro- 

 boscis stout, strongly swollen at the base, pointed api- 

 cally, rounded and curved on the ventral aspect, sub- 

 quadrate on the apical third which bears a conspicuous 

 tuft of stiff dorsal pile. Ventral surface with a deep 

 longitudinal fissure throughout its length; base below 

 with a tuft of stiff bristles. Proboscis usually directed 

 forward. Palpus clearly of two segments, the first seg- 

 ment hemicylindroid, but distinctly fused; second seg- 

 ment not porate, cylindrical with numerous stout 

 bristles. Antenna usually attached at or above the up- 

 per eighth of the head, or in the subgenus Eudioctria 

 Wilcox and Martin, attached just above the upper third. 

 Antenna elongate, distinctly longer than the head; seg- 



