1804.] 275 



convex, whitish, the space on each side bhick ; postscutellum black with 

 a transverse whitish spot on the middle ; metathorax rufous, stained 

 with blackish on the disk, the elevated lines obsolete, the central ai-ea 

 small, elongate and ill-defined. Wings long and ample, hyaline, iride- 

 scent; nervures and stigma black, pale at base; areolet wanting, the 

 2nd recurrent nervure somewhat angular in the middle. Legs slender, 

 posterior pair long ; pale rufous ; the four anterior coxaa, the trochan- 

 ters and most of the tarsi, whitish; posterior tibia) whitish, its tip and 

 extreme base, black, their tarsi entirely black. Abdomen subsessile, 

 elongate-subovate, black, shining towards the tip ; basal segment grooved 

 down the middle ; apical margins of all the segments narrowly whitish, 

 rather indistinct on the first three segments ; ventral segments white. 

 Length Si lines; expanse of wings 7 lines. 

 Hah. — Illinois. Dr. Samuel Lewis. 



5. Tryphon pleuralis, n. sp. 



Black; mouth and tegulse, yelIowish-whit5; pleura, scutellum and legs, ru- 

 fous : wings hyaline, areolet small, oblique, subpetiolated ; abdomen with the 

 apical margins of the dorsal segments pale: abdomen subpetiolated. 



Fem((ff. — Black, subopaque, clothed with a very short, whitish pile ; 

 clypeus, mandibles, a spot on the cheeks beneath, and the palpi, whitish; 

 antennae slender, rather longer than the body, piceous, tinged with yel- 

 lowish towards the base beneath ; mesothorax and pectus black, pleura 

 and scutellum dull rufous, as well as a spot behind the scutellum ; 

 tegulfe pale yellowi.sh-white ; metathorax entirely black, the elevated 

 lines obsolete, the central area elongate, moderate. Wings hyaline, 

 beautifully iridescent ; nervures and stigma blackish, pale at base; are- 

 let small, obliquely subtriangular and subpetiolated; the transverse 

 cubital nervure within the submarginal cell very much arcuated towards 

 the costa, the 2nd recurrent nervure straight, or slightly oblique. Legs 

 slender, pale rufous; the four anterior coxte, trochanters and tarsi, 

 whitish ; the posterior tibiae and tarsi and the tips of the other tarsi 

 blackish, extreme base of the posterior tibiaj whitish. Abdomen sub- 

 petiolated or slightly sub.sessile ; black, shining towards the apex ; ex- 

 treme apical margins of the segments whitish, obsolete or subobsolete 

 on the three basal segments, and distinct on the apical ones, the lateral 

 margins of which are rather broadly marked with white ; first segment 

 longer than the second, much narrowed toward the base, and again 



