238 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



conspicuous bristles across the epistoma. Length 12 

 to 33 mm. 



Head, lateral aspect: The head is short, the face also 

 short but is a little more protuberant ventrally above 

 the epistoma; the subepistoma is large and oblique, 

 slightly concave. The occiput is narrow but more 

 prominent and thick medially, with on the upper three- 

 fifths a row of very stout bristles and additional long, 

 stiff pile and below on the lower part a dense bushy tuft 

 of rather long pile. The proboscis is large, curving 

 downward, cylindroid, with thick base but with a prom- 

 inent, thin dorsal ridge; the apex is pointed with a 

 rounded tip and abundant pile, the basal half below 

 bears numerous, long hairs. The palpus is large and 

 has two segments; the first segment is excavated, the 

 second segment is cylindrical ; apex and all surfaces ex- 

 cept medial with numerous long, stiff bristles and hairs. 

 The antenna is attached at or above the upper third of 

 the head. It is slender and elongate, a little longer than 

 the head. The first two segments are slightly elongate, 

 with the second longer than the first ; both bear a num- 

 ber of stout, long setae ventrally and also dorsally but 

 the second segment has a conspicuous long, stout, ven- 

 tral, subapical bristle. Third segment of uniform 

 width or very slightly and gradually attenuate and is 

 from iy 2 to 2 times as long as the combined length of 

 the first two segments. The third segment, at the end, 

 has a short, stout, wide microsegment, with oblique, 

 truncate apex carrying a short, concealed spine. Dor- 

 sal margin of the third segment with 6 to 10 long, con- 

 spicuous setae or short bristles. 



Head, anterior aspect: The head is quite wide, the 

 eyes flattened with the anterior facets enlarged. The 

 face is wide, slightly diverging below. The face is pu- 

 bescent, with a supraepistomal mystax of very stout, 

 long bristles. Front and vertex of nearly the same 

 width as the face below the antenna. Front with nu- 

 merous, fine, long hairs on the eye margins. Vertex 

 with 5 pairs of long, stout bristles and a few, slender 

 hairs. Vertex shallowly excavated, ocelli set on a low 

 tubercle. 



Thorax : The mesonotum is gently convex with fine, 

 erect, scattered pile, including the humerus. The hu- 

 merus also bears 7 very stout, spinous bristles. Later- 

 ally the stout bristles consist of 4 notopleural, 2 supra- 

 alar, 3 postalar, and the scutellar margin with 3 pairs 

 of bristles and marginal pile. Scutellar disc fiat, with- 

 out pile and with convex margin. The lateral propleu- 

 ron is pilose, the pronotum with long, weak bristles and 

 pile. Upper sternopleuron and whole posterior border 

 of mesopleuron with dense, long pile. Pteropleuron 

 and hypopleuron without pile. Metapleuron convex, 

 bare behind, but with a long, wide band of numerous, 

 long, slender bristles and stiff hairs. Lateral and ven- 

 tral metasternum with long, stiff pile. Metanotal 

 callosity exceptionally bullose and micropubescent or 

 pollinose only. Pleuron generally pollinose. Post- 

 metacoxal area membranous. Basalare without pile or 

 bristles; tegula with setae; presternum dissociated. 



Legs: The femora are quite stout without being 

 greatly thickened and rather short; the hind tibia is 

 somewhat thicker than the corresponding femur. Hind 

 tarsus also thickened and stout. The pile of the hind 

 femur is densely appressed, fine setate; it bears only 

 a row of 7 or 8 very stout, lateral, tuberculate bristles, 

 which do not extend to base or apex. Hind tibia with 

 equally stout, long bristles, 1 dorsocentral, 1 dorsal sub- 

 apical, 5 dorsolateral, 3 ventrolateral on the distal half, 

 with the usual medial brush of setae; its apex bears 

 4 ventral and 6 medial bristles. Middle femur with 2 

 subapical posterior and 4 central anterior bristles. 

 Middle tibia with 3 short dorsal, 7 long anterior, 4 short 

 basal anterior, 10 posterior, and also 4 exceptionally 

 long, postero ventral bristles. Apex with 13 bristles. 

 Anterior femur with 3 posterior subapical bristles. 

 Anterior tibia with 15 to 22 dorsal bristles in a double 

 row. The apex of this tibia bears 8 bristles and a long, 

 basally thickened, apically pointed, narrow, curved, 

 somewhat twisted clawlike spine. Basitarsus with fine 

 microdenticles. All tarsi end in stiff, unswollen em- 

 podium, well developed pulvilli and divergent, sharp 

 claws. 



Wings: The wings are often tinged with brown. 

 Marginal cell open but by a little less than its maximal 

 width. Second submarginal cell narrowed basally, 

 arising wholly above the third vein and strongly flared 

 apically so that both branches of the third vein end 

 well away from the apex of the wing, the posterior 

 branch farthest from the apex. Posterior cells widely 

 open except the fourth which is closed with a short 

 stalk. Anal cell closed in the margin. Alula large, 

 ambient vein complete. The anterior branch of the 

 fourth vein originates rather far back on the second 

 basal cell and the middle end vein of the second basal 

 cell is quite short. 



Abdomen : The abdomen is robust to the end of the 

 fourth segment and as wide as thorax. These first seg- 

 ments have more matted pile and sometimes pile of a 

 different color. Sides of first tergite with a dense tuft 

 of copious, bristly and bushy pile and no bristles. 

 Fifth and remaining segments tapered and narrowed. 

 The pile varies from short to long. The female termi- 

 nalia bears 5 pairs of remarkably stout, long, spoon- 

 shaped, almost truncate, dorsal spines. Ventral plate 

 with a medially notched, rather large, subconical pro- 

 jecting end piece and numerous short, fine, bristly hairs. 

 Male terminalia comparatively small considering the 

 size of the species. The epandrium is unusually small 

 and short but fully cleft, each half rounded at apex; 

 the proctiger, perhaps in consequence, is unusually long 

 and large and projects beyond. The gonopod is the 

 dominant element and is high, extensive, convex 

 basolaterally, and bears on each side two distal processes 

 which are stout, elongate, with blunt apex. Hypan- 

 drium large, but comparatively short and obtuse, 

 leaving the cavity open and exposed ; internally there 

 appear to be one or two pairs of more slender processes. 

 The terminalia are rather densely beset with long, 

 bristly hairs or very slender bristles. 



