116 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



ventrally; its tibia similar to the middle tibia, the 

 anterior bristles lacking. Apex with very long bristles ; 

 no tibial spine present. All tarsi end in long claws, 

 long, spatulate pulvilli and a long, bladelike empodium. 



Wings: The length of the wings is 2V 2 times the 

 width. Marginal cell widely open. The anterior 

 branch of the third vein ends just before the wing 

 apex and is gently arched at the base. First posterior 

 cell fully open, the fourth slightly narrowed or rarely 

 greatly narrowed. The anal cell closed with a short 

 stalk, the middle vein ending in the second basal cell, 

 short to quite long, ambient vein complete; the anterior 

 cross vein lies before the middle of the discal cell. 



Abdomen : The abdomen is comparatively robust in 

 some species and in others more slender. It is gently 

 and only slightly tapered ; the prominent male termi- 

 nalia usually wide. Much of the surface is pollinose 

 with fine, flat, appressed pile or subappressed setae in 

 the middle of the tergites and the lateral margins with 

 setae, or especially in males with abundant, long, fine 

 pile. Males with seven tergites, the last two shorter, 

 and females with eight tergites ; in the female the eighth 

 tergite may be even longer than the seventh and is 

 highly polished, without pollen. Sides of first tergite 

 with a number of quite weak bristles. Male terminalia 

 large, prominent, obtuse and fully rotate. The most 

 conspicuous element is the large bulboconvex epan- 

 drium which is fully cleft into forceps with large re- 

 cessed proctiger. The ventral half is composed of a 

 short but conspicuous and obtuse structure which I 

 interpret as the gonopod fused on each side with the 

 hypandrium. Females with acanthophorites and 8 to 

 10 long, slender spines on each side ; the ventral element 

 consists of either a flat plate or a boatlike, or trough- 

 like, partly compressed plate, produced apically and 

 narrowly cleft on the produced part. 



As far as known today this genus is almost confined 

 to Europe and the United States. They are most nu- 

 merous in the western part of America and in eastern 

 central Europe. A species is known from Alaska at a 

 latitude equivalent to the middle of Sweden. 



Distribution : Ncarctic : Lasiopogon actius Melander 

 (1923); albidus Cole and Wilcox (1938); aldrichii 

 Melander (1923) ; arenicola Osten Sacken (1877) ; 

 aridus Cole and Wilcox (1938; atripennis Cole and 

 Wilcox (1938) ; bivittatus Leow (1866) ; calif ornicus 

 Cole and Wilcox (1938 ; canus Cole and Wilcox (1938) ; 

 carolinensis Cole and Wilcox (1938); chaetosus Cole 

 and Wilcox (1938) ; cinereus Cole (1919) ; currani Cole 

 and Wilcox (1938) ; delicatulus Melander (1923) ; 

 dimichi Cole and Wilcox (1938) ; drabicolum Cole 

 (1916); fumipennis Melander (1923), fumipennis 

 olympia Cole and Wilcox (1938) ; gabrieli Cole and 

 Wilcox (1938) ; hinei Cole and Wilcox (1938) ; lift oris 

 Cole (1924) ; martinensis Cole and Wilcox (1938) ; 

 monticola Melander (1923) ; ohlahomensis Cole and 

 Wilcox (1938) ; opaculus Loew (1874) ; pac'ficus Cole 

 and Wilcox (1938) ; pugeti Cole and Wilcox (1938) ; 



quadrivittatus Jones (1907) ; ripicola Melander (1823) ; 

 shermani Cole and Wilcox (1938) ; slossonae Cole and 

 Wilcox (1938) ; terricola Johnson (1900) ; testaceus 

 Cole and Wilcox (1938) ; tetragrammus Loew (1874) ; 

 trivittatus Melander (1923) ; loillametti Cole and Wil- 

 cox (1938) ; yuhonensis Cole and Wilcox (1938) ; zona- 

 tus Cole and Wilcox (1938) . 



Palaearctic. Lasiopogon appeninus Bezzi (1921) ; 

 bezzii Engel (1929) [ = tarsalis Bezzi (1917)]; cinctus 

 Fabricius (1781) [ = cinctellus Meigen (1820), hirtellus 

 Fallen (1814)]; delphinensis Bezzi (1921); grajus 

 Bezzi (1921) ; immaculatus Strobl (1893) ; intermedins 

 Oldenberg (1924); lichtwardti Oldenberg (1924); 

 macquarti Perris (1852); montanus Schiner (1862) 

 [=bellardii Jaennicke (1867), macquarti Schiner 

 (1856) not Perris]; nanus Oldenberg (1924); nitidi- 

 cauda Bezzi (1921); pilosellus Loew (1847) [ = hirtel- 

 lus Meigen (1820) not Fallen] ; pusillus Bezzi (1921) ; 

 spinisquama Bezzi (1921) ; tarsalis Loew (1847) ; tri- 

 dentinus Bezzi (1921) ; velutinus Bezzi (1921). 



Oriental. Lasiopogon gracilipes Bezzi (1921) ; 

 solox Enderlein (1914). 



Country unknown. Lasiopogon acratus Walker 

 (1849). 



Larva and pupa of Lasiopogon cinctus Fabricius 

 have been mentioned by Lundbeck, 1908, and described 

 and illustrated by Melin, 1923. 



Subgenus Alexiopogon Curran 



Figube 63 



Alexiopogon Curran, Families and genera of North American 

 Diptera, New York, p. 117, 183, 1934. Type of subgenus: 

 Lasiopogon terricola Johnson, 1000, by original designation. 



Very small flies closely related to Lasiopogon Loew 

 of which it is at most a subgenus. They are dis- 

 tinguished from Lasiopogon, sensu stricto, by the 

 absence of dorsocentral bristles, and the absence of 

 bristles or long hairs upon the scutellar margin ; some, 

 fine, short, apical hairs may be present. Length 5 to 

 7 mm. 



Head, lateral aspect : The head is comparatively long, 

 the face on the upper third beneath the antenna quite 

 plane with the eye margin and moderately protuberant, 

 gibbous and gently rounded on the lower portion. The 

 eye is strongly convex anteriorly with considerable re- 

 cession anteroventrally and very convex posteriorly on 

 the upper half; the occiput is prominent on 

 the upper fifth. Pile of the occiput abundant, fine and 

 long on the lower half ; on the upper half the pile is re- 

 placed by fine bristles which are at first short, becoming 

 longer and more strongly curled towards the vertex. 

 Proboscis short but robust, the apex obtusely rounded, 

 almost truncate, extending a short distance beyond the 

 face, directed forward at a slight downward angle. 

 There is a high medial ridge extending to the outer 

 fourth; the apex bears a few, stiff hairs and the base 

 below some long pile. 



