NATURAL SCIENCES OF PHILADELPHIA. 315 



rupted b}' the first marginal cell which is clearly hyaline, broadly 

 dark fuliginous; inner radial nerve nearl}- straight, very i-lightly 

 curved near costa, first submarginal cell without membranaceous 

 spots ; abdomen robust, entirely black, with a bluish reflection, 

 first segment broadly and rather suddenly dilated at apex. Length 

 16 lines. 



Orizaba. (Sumichrast, No. 64.) A very robust and distinct 

 species. 



Genus NOTOTRACHYS, Marshall. 



Nototrachys fuscatus. 



2'rachyiiotusfuscatus, Cress., Proc. Ent. Soc. Phil., iv. p. 50. 



Orizaba, Cordova. (Sumichrast, No. 138.) 



Genus EXOCHILIJM, Wesm. 



Exochilum mundum. 



Ophion iiiundus^ Say, Bost. Journ. Nat. Hist., i. p. 228. 



Cordova. 



Genus THYREODON, Brulle. 



1. Thyreodon niger, n. sp. 



% 9. Entirely black, shining, more slender in form than morio^ 

 Fabr. ; antennteof 9 entirely black, that of S more or less yellowish 

 beneath ; impressed lines of mesothorax longitudinally roughened ; 

 pleura polished ; metathorax oi)aque, closely reticulated, clothed 

 with very short, dense black pubescence, posterior face broad and 

 flat, the flanks protuberant ; scutellum deeply excavated at base ; 

 wings black, with a brassy gloss ; legs shining, tibije, tarsi, and 

 abdomen with brownish sericeous pile ; first segment of abdomen 

 slender, slightly dilated at apex, second segment with a broad 

 shallow groove on each side. Length 13i lines. 



Cordova. (Sumichrast, No. 65.) Much like morio Fabr., but 

 more slender, and distinguished at once by the black antennae. 



2. Thyreodon maculipennis, n. sp. 



1, 9 . Entirely black, shining, with a more or less distinct bluish 



reflection; antennae ; wings violaceous black, the 



anterior pair with a large subquadrate hyaline spot, covering most 

 of the first submarginal and first discoidal cells; metathorax 



