WILLIAM G. DIETZ 129 



Pachyrhina sodalis nictans subsp. n. 



Differs from P. sodalis Loew as follows: 



Head deep ferruginous; mouthparts and palpi dark yellow. Frontal pro- 

 longation and nasus shining, beset with long, black hairs. Antennae robust, 

 scapal joints dark ferruginous, first flagellar joint yellowish -fuscous, remainder 

 of flagellum dark brown; joints, except the outer ones, more deeply excised 

 below. Face opaque, occiput with broad, shining triangle, projected ante- 

 riorly upon the vertex. 



Thoracic dorsum dark, testaceous, almost~pellucid, stripes indistinctly de- 

 fined. Postnotum sordid yellow on the sides. Pleura sordid yellow, with 

 moderate whitish sheen. Halteres yellowish-brown, club brown. Legs long, 

 slender, yellowish; pubescence very short, blackish, tibiae slightly infuscate 

 at the apex, shorter than the metatarsi; outer tarsal joints infuscate. Wings 

 as in sodalis. Abdomen dark orange-yellow, an ill-defined, brownish dorsal 

 stripe, eighth tergite darker, reddish-brown; a lateral row of black strigae 

 and a ventral row of similar spots. Eighth sternite reddish-brown, not emar- 

 ginate. Hypopygium ferruginous; ninth tergite reddish -brown, very short, 

 deeply and narrowly emarginate in the middle; outer appendages dark yellow, 

 not markedly attenuated towards the apex. 



Length, 17 mm.; wing, 13.5 mm. 



Holotype: d" ; Bear Creek, Colorado. June 29, 1914. (E. J. 

 Oslar.) 



The unique specimen in my possession is defective. In its 

 unicolorous, blackish antennal flagellum and shining occiput it is 

 closely allied to P. sodalis Loew, but its general dark ferruginous 

 color, the stouter, more deeply excised flagellar segments and the 

 highly polished thoracic dorsum, with its ill-defined stripes, give it 

 a distinctive appearance. In its dark ferruginous appearance 

 it resembles P. cingulaia; but is readily distinguished by its uni- 

 colorous flagellum, the wings without yellow tint and the abdom- 

 inal tergites without latero -posterior black margins. 



Pachyrhina costomarginata spec n. (PI. V, fig. 13.) 



Yellow. Occiput opaquejwith shining, triangular spot. Antennae, with the 

 exception of the three basal joints, dark brown. Thoracic stripes shining, 

 interspaces opaque. Wings slightly infuscate, costal cells brown, stigma pale 

 fuscous. 



Male. Length, 9.5 mm.; wing, 8 mm. 



Head deep yellow. Frontal prolongation with obscure, ferruginous, median 

 stripe, nasus beset with black [hairs, mouthparts and palpi dull yellow, first 

 joint infuscate at apex. Antennae of moderate thickness, pubescence dense, 

 whitish; three basal joints yellow; joints four and five dark yellowish-brown^ 

 following joints darkjbrown, segments cylindroidal, basal enlargement marked 

 with a whorl of few, rather short, black setae. Face pale yellow; frontal 



TRANS. AM. ENT. SOC, XLIV. 



