OF PHILADELPHIA. 857 



black: feet yellowish, a line beneath the thighs black: venter 

 on the posterior disk ferruginous. 



Length more than three-tenths of an inch. 



BACCHA. 



B. COSTATA. — Body black ; tcrgum with white bands. 



Inhabits Indiana. 



Head silvery ; a shining black line from the vertex to the 

 mouth, much constricted on the middle of [162] the front: an- 

 tennae obsoletely honey-yellow at base : occiput plumbeous with 

 a silvery reflection : thora.\^ black : poisers white : wings hyaline 

 with a somewhat narrow costal margin, not reaching the tip : 

 scutel margined with yellow : tergum black ; first, second, and 

 third segments with an obli(£ue white spot on each side at base, 

 and remaining segments tipped with white ; feet black ; anterior 

 pairs, base of the tibia and tip of the thighs honey-yellow ; pos- 

 terior tibia honey-yellow at base. 



Length half an inch. 



XYLOTA Meig. 



X. ARQUATA. — Blackish ; tcrgum fulvous with white arcs. 



Inhabits Mexico. 



Body blackish : head above with greenish hair, below the an- 

 tenna) with whitish hair: vertex blackish; tubercle of the an- 

 tennae black : antennae black-fuscous : hypostoma with a naked 

 black vitta before, and another on each side, from the anterior 

 canthus of the eye to the tip : thorax with short hair; with three 

 slender lines on the disk : scutel yellowish at tip : wings hyaline: 

 terguui fulvous; first segment black; remaining segments, ex- 

 cepting the terminal one, with a blackish middle and whitish 

 transverse arquated line each side : feet, knees and posterior 

 tibiae honey -yellow : venter yellowish, more dusky at tip. [163] 



Length seven-twentieths of an inch. 



Var. a. Tergum black, with transverse arquated lines : poste- 

 rior margins of the segments yellow. 



MILESIA Fabr. Meig. 

 M. BARDA. — With yellow hair ; tergum black, yellow at base. 

 Inhabits Indiana. 



Body black : hypostoma with silvery hair and longitudinal, 

 1829.] 



