110 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



broad and low, with large ocelli. Anterior eye facets 

 exceptionally enlarged. 



Thorax: The thorax is everywhere pollinose; the 

 mesonotum has abundant, short, setate pile undiffer- 

 entiated anteriorly and the medial line with a narrow, 

 bare stripe. The mesonotal complement of bristles con- 

 sists of 1 stout notopleural, no suparaalar, 1 postalar, 

 and no scutellar bristles. Scutellum is flat with minute 

 setae on the margin. On the pleuron, the pile is re- 

 stricted to rather abundant, fine hairs on the pro- 

 pleuron, a very few shorter, inconspicuous hairs on the 

 posterior mesopleuron and a conspicuous, single, verti- 

 cal row of bristles on the metapleuron containing 9 or 

 10 elements. Squamae with a fine, long fringe. Lat- 

 eral slope of the metasternum is without pile; ventral 

 metasternum chitinized; postmetacoxal area membra- 

 nous and densely pubescent. 



Legs: All the femora are stout, but the middle and 

 anterior femora are rather strongly swollen, especially 

 over the middle and base. Hind femur with a dorsolat- 

 eral row of 6 stout bristles, a ventromedial row of 8 

 weaker bristles; dorsal apex with a bristle on each side; 

 middle femur with a single, stout, anterodorsal, sub- 

 apical bristle and 2 similar posterodorsal bristles. 

 Anterior femur with 3 stout bristles, 2 of them dorsal ; 

 these lie at the middle of the femur, at the outer fifth 

 and at apex. Tarsi and tibiae with longer, stouter 

 bristles. Hind tibia with 2 ventrolateral and 4 weak 

 dorsal bristles, the apex with 8 bristles. Middle tibia 

 with 1 posterior subapical, 3 stout, posteroventral, and 



1 stout and 2 minute anterodorsal bristles. On the ante- 

 rior tibia there is a single, minute, basal, anterodorsal 

 bristle and 4 prominent posterior bristles of increasing 

 length. The posterior bristles of the anterior and 

 middle tarsi and lateral bristles of the hind tarsi are 

 especially long and stout. Claws large, long, sharp; 

 the pulvilli long and slender; the empodium long as 

 the claws and flattened. Legs everywhere pollinose 

 with short, appressed pile. 



Wings : The marginal and all the posterior cells are 

 open ; anal cell closed with a short stalk. Ambient vein 

 complete. Middle end vein of the second basal cell is 

 short. Alula quite linear. 



Abdomen: The abdomen is longer than the wings, 

 robust, pollinose, and nearly as wide as the thorax. 

 The males have nine well developed tergites; the fe- 

 males with eight, the last tergite is as long as the pre- 

 ceding tergite. Sides of the first tergite with a row of 



2 to 5 stout bristles. Male terminalia enclosed by the 

 deeply sulcate, somewhat down-turned, arched and 

 hoodlike epandrium or ninth tergite. Female termi- 

 nalia with 5 pairs of long, bluntly pointed spines; 

 eighth sternite deeply notched. 



These flies frequent sandy or muddy shores of rivers 

 or any large body of water with a preference for damp 

 sand. They are often found on weathered driftwood 

 from which the bark has fallen. 



Distribution: Nearctic: Neopogon coquilletti Bezzi 

 (1910) ; salinus Melander (1923) ; snowii Bezzi (1910) ; 

 trifasciatus Say (1823) [ = candidus Macquart (1846), 



fasciventris Macquart (1849), gelascens Walker (1860), 

 plagiatus Walker (1848)]. 



Neotropical: Neopogon schnusei Bezzi (1910). 



Genus Clinopogon Bezzi 



Figures 59, 60, 121, 448, 939, 1686, 1818, 2045 



Clinopogon Bezzi, Ann. Mus. Nat. Hungarici, vol. 8, p. 153, 1910. 

 Type of genus: Clinopogon sauteri Bezzi, 1910, by original 

 designation. 



These are flies of less than medium size. Related to 

 Stichopogon Loew through the widely divergent front 

 and face. These flies are characterized by the wide 

 face, the long, dilated third antennal segment, the 

 abundant, long tufts of pile on the mesopleuron, sterno- 

 pleuron and the whole scutellum. Face with a con- 

 spicuous, dense, arched and shieldlike mat of down- 

 turned pile, which in the middle of face reaches nearly 

 to the base of the antenna. The abdomen is broad at 

 the base and flattened, as wide as the thorax and 

 strongly tapering apically. Length 12 to 15 mm. 



Head, lateral aspect: The length of head is three- 

 fourths of the height. The face in profile is quite plane 

 with the eyes beneath the antennae, slightly and gradu- 

 ally produced below, more prominent below as the eye 

 recedes ; the anterior facial margin is plane and vertical. 

 The eye is unusually long and strongly recessive be- 

 low. The occiput is only narrowly produced through 

 the middle, obliterated on the upper third, but quite 

 prominent and thick below; its pile is fine and abundant 

 dorsally but dense and long, with the ends thinned and 

 curled on the ventral half. Deeply behind the vertex 

 there is a row of 4 pairs of moderately stout, pale 

 bristles which extend backward rather than upward. 

 The proboscis is small, cylindrical, slender, with obtuse 

 apex bearing subapically a circlet of stiff pile; the 

 dorsal ridge absent, the base below with a number of 

 fine, long hairs. The proboscis is directed obliquely 

 forward. Palpus of two segments, the second cylindri- 

 cal, slender, without apical hair or bristles. The an- 

 tenna attached at or just below the upper third of the 

 head; antenna of moderate length, the first two seg- 

 ments short, of equal length. The third segment is 

 strongly compressed laterally, tapering gradually from 

 the base to near the middle at which point it is widest ; 

 before the apex it is considerably narrowed and bears a 

 short, thick, microsegment carrying apical spine. The 

 pile of the first two segments consists of a few very fine, 

 short hairs. 



Head, anterior aspect : The width of head is IV2 times 

 the height. The face below antenna is nearly one-sixth 

 the head width and divergent below ; subepistomal area 

 moderately large, plane and pubescent. The face is 

 pubescent with, along the lower anterior and lateral 

 margin, a dense mat of long, flattened pile arising on a 

 triangular area in the lower middle portion of the face, 

 forming a curtain or screen around the epistoma. The 

 front and vertex are very strongly divergent, the latter 

 more than half as wide as the head; sides of front 



