106 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



tibia with 5 posteroventral, 3 weak anterodorsal, 2 

 anteroventral, and 2 ventral bristles. Anterior tibia 

 with 3 well developed posteroventral bristles. Claws 

 sharp, pulvilli well developed and slender, and em- 

 podium half as long as the claws. 



Wings: The marginal and posterior cells widely 

 open, anal cell closed with a short stalk, base of an- 

 terior branch of third vein strongly arched. The sec- 

 ond basal cell ends in 2 veins and sometimes is fused for 

 a considerable distance beyond. The anterior cross- 

 vein enters the discal cell shortly before or shortly after 

 the basal third. Ambient vein complete. Alula 

 absent. 



Abdomen: The abdomen is comparatively robust 

 and rather flattened towards the base; nearly as wide 

 as the thorax and at least as wide as the mesonotum. 

 The abdomen is pollinose with fine appressed pile, 

 longer on the sides of the first tergite ; bristles are ab- 

 sent on the first tergite. The male has eight tergites, 

 the eighth quite short, and the ninth or epandrium un- 

 cleft, exceptionally long and turned vertically or 

 obliquely downward as a broad deep hood with curved 

 sides enclosing the terminalia. Gonopod quite small 

 and short, largely concealed within the bowl of the 

 epandrium. Proctiger small and exposed. Hypan- 

 drium very short and medially divided. Females with 

 eight tergites, the last as long or longer than the 

 seventh and with five pairs of long, apically rounded 

 spines. Eighth sternite deeply notched or cleft almost 

 to its base, the edges apposed. 



This genus contains some of the smallest of asilids. 

 The species frequent sandy areas and are common along 

 shores or even garden spots. 



Distribution: Nearctic: Stichopogon abdominalis 

 Back (1909) ; arenicola Wilcox (1936) ; argenteus Say 

 (1823) ; colei Bromley (1934) ; fragilis Back (1909) ; 

 pritchardiBvovaley (1951). 



Neotropical: Stichopogon aedon Walker (1849); 

 catulus Osten Sacken (1887) ; ocrealis Rondani (1863). 



Palaearctic : Stichopogon albellus Loew (1856); 

 aequetinctus Becker (1910) ; albofasciatus Meigen 

 ( 1820) [ = arenivagus Koch ( 1872) , dziedzickii Schnabl 

 (1882), nigrifrons Loew (1847), ripicola Dufour 

 (1833)]; auctus Bezzi (1912); barbiellinii Bezzi 

 (1910); barbistrellus Loew (1854); beckeri Bezzi 

 (1910) ; canariensis Becker (1908) ; candidus Becker in 

 Becker and Stein (1902) ; canus Seguy (1932) ; Cauca- 

 sians Bezzi (1910) ; chrysostoma Schiner (1867) [ = lu- 

 ddiventris Becker (1903)]; dorsatus Becker (1915); 

 dubiosus Villeneuve (1920) ; elegantulus Wiedemann in 

 Meigen (1820) [=aequecinctus Costa (1883), frauen- 

 feldi Egger (1855), riparius Loew (1871), tener Loew 

 (1857)] ; flaviventris efflatoun (1937) ; inaegualis Loew 

 (1847) ; inconstans Wiedemann (1828) ; Jcerteszi Bezzi 

 (1910); marinus Efflatoun (1937); muticus Bezzi 

 (1910) ; punctiferus Bigot (1878) ; pusio Macquart 

 (1849) ; pygmaeus Macquart (1849) ; scaliger Loew 

 (1847) [ = congener Loew (1856)], scaliger Jcrueperi 

 Bezzi (1910) ; schineri Koch (1872) [=spinimanus 



Pokorny (1887)]; septemcinctus Becker (1908); sur- 

 coufi Villeneuve (1920). 



Ethiopian: Stichopogon caffer Hermann (1907); 

 dilutus Walker (1851) ; grossus Bromley (1947) ; her- 

 manni Jiezzi (1910) ; maculipennis Engel and Cuthbert- 

 son (1939) ; punctum Loew (1851) [=punctatus Loew 

 (1852)] ; unicolor Eicardo (1925). 



Oriental: Stichopogon albicapillus Wulp (1872); 

 cinctellus Bigot (1878); gymnurus Oldroyd (1948); 

 infuscatus Bezzi (1910) ; maculipennis Brunetti 

 (1928) ; meridionalis Oldroyd (1948) ; nicobarensis 

 Schiner (1868); peregrinus Osten Sacken (1882); to- 

 mentosus Oldroyd (1948). 



Australian : Stichopogon bancrofti Hardy ( 1934) ; 

 congressus Walker (1861) ; minor Hardy (1934) ; ob- 

 scurus Hardy (1928) ; vernaculus White (1917) ; sca- 

 laris Bigot (1878). 



Subgenus Dichropogon Bezzi 



Figuees 62, 453, 937, 946 



Dichropogon Bezzi, Ann. Mus. Nat. Hungarici, vol. 8, p. 133. 

 1910. Type of subgenus. Stichopogon schineri Koch, 1872, 

 by original designation. 



Quite small, slender, pollinose flies, which closely re- 

 semble Stichopogon Loew, to which they are quite 

 closely related. The mystax at the epistoma is stout 

 and roof like or tectiform. The ocellar bristles are weak 

 and indistinct, but in Stichopogon are strong. In 

 Stichopogon the mesopleuron is sparsely pilose or bare ; 

 in Dichropogon it is pilose. Base of fourth posterior 

 cell with a short petiole or sessile. In contrast to C'lino- 

 pogon Bezzi the furcation of the third vein is long and 

 narrow. There are 2 bristles on the supraalar region. 

 As in all members of the tribe the front and vertex are 

 widely expanded, the lateral metasternum without pile. 

 Length 7 mm. 



Engel (1930) places the following, additional species 

 in this subgenus: canariensis Becker, caucasicus Bezzi, 

 pusio Macquart. 



Head, lateral aspect: Eye very strongly convex an- 

 teriorly and with marked recession posteriorly which 

 begins at the middle of the eye. Occiput thick in the 

 middle and especially prominent below, but on the dor- 

 sal half of the head sloping rapidly down to the eye 

 margin below the vertex. Occipital pile above quite 

 scanty, abundant below but only moderately long. 

 Bristles restricted to the postvertical region, where they 

 form a row of about eight stout bristles. Proboscis 

 short, rather stout, with a high dorsal ridge somewhat 

 swollen at the base; the apex is bluntly pointed. The 

 base with fine pile below; apical pile minute. Palpus 

 quite slender and cylindrical, of two segments, with- 

 out pile or bristles on the apical half. Antenna at- 

 tached just above the middle of the head, rather short 

 but slender. The first segment is minute, from a third 

 to a fourth as long as the distally expanded, beadlike, 

 second segment. Third segment iy 2 times as long as 

 the combined length of the first two. Slightly tapered 



