NATURAL SCIENCES OP PHILADELPHIA. 161 



prominent and tubcrciiliform ; areolet minute, open ; ulidomeu 

 smootli and opaque. Length 4^ lines. 

 Orizaba. 



22. Mesostenus incertus, n. sp. 



9. Head, antennae and tliorax, black; face, clypeus, orbits 

 interrupted posteriorly, spot on mandibles, annulus on antenna, 

 collar, tegulae, line before, spot beneath, spot on disk of meso- 

 thorax, scutellums, two oblique lines in front, oblique mark on 

 pleura, space behind base of wings, two elongate marks on poste- 

 rior face of metathorax covering spines, a mark on flanks, and 

 four anterior coxsb, white ; wings hyaline, apex dusky, nervures 

 black; posterior coxa?, femora, and abdomen hone3'--yellow, remain- 

 der of legs bright yellow; four anterior femora more or less black 

 behind; in one specimen the first abdominal segment is 3'ellow 

 with a large black spot near apex. Upper margins of prothorax 

 prominent; raesothorax punctured; metathoi'ax reticulated at 

 base and sides, transversely striated posteriorly, spines prominent 

 and subacute; areolet quadrate, closed; abdomen smooth and 

 shining. Length 5| lines. 



% . Upper lateral angles of prothorax tuberculiform ; black 

 spot on middle of scutellum ; posterior coxae with black stripe, 

 their femora entirely black ; first and middle of second abdominal 

 segment black, remainder of abdomen dull houey-j^ellow. Length 

 4^ lines. 



Orizaba ; Cordova. 



23. Mesostenus animatus, n. sp. ' 



9 Head, antennae and thorax black; face except broad mark 

 above clypeus, mouth, clypeus, orbits broad on cheeks, broad 

 annulus on antennae, collar, tegulae, line before, spot beneath, two 

 short discal lines on mesothorax, scutellum, two oblique lines in 

 front, spot on postscutellum, space behind base of wings, flanks of 

 metathorax, two elongate marks on posterior face covering tuber- 

 cles, large mark on eacli side of pleura, four anterior coxae and 

 trochanters, spot at base of posterior coxae and their tarsi except 

 extreme base and apex which are black, all white; wings hyaline, 

 nervures fuscous ; legs and abdomen pale honey-yellow, base and 

 apex of first and apical margins of second, third, and fourth seg- 

 ments whitish. Smooth, shining; mesotliorax strongly* trilobate ; 

 metathorax rugulose, with two transverse carinaa, the posterior 



