NATURAL SCIENCES OF PHILADELPHIA. 155 



on collar, tegulfc, spot benitli, a furcate mark on disk of meso- 

 tliorax, sciitellum, dot on postscutelliun and apical margins of 

 abdominal segments, white or j-ellovvish-wliite ; oltliqne mark on 

 pleura, space behind base of wings, metathorax except broad black 

 band at base, and the legs, dull honey-yellow ; base of trochanters, 

 posterior knees and tips of tarsi, blackish ; most of posterior tarsi 

 whitish; wings hyaline, dusk^^ at apex, nervures fuscous. Meta- 

 thorax rugulose, smooth at base, with two transverse carinas, the 

 posterior one produced into a prominent flattened tubercle on each 

 side ; abdomen very slender at base, the first segment with a small 

 tubercle on each side before apex ; areolet minute, open. Length 

 5^ lines. 



Z. Yery slender; annulus on antennoe broader and entire; 

 face white, with two central black dots ; two white lines before 

 tegulse ; metathorax without tubercles; tips of posterior tibiui 

 black, their tarsi white. Length 5 lines. 



Orizaba; Cordova; Mirador. (Sumichrast, Xo. 104.) Common. 



9. Mesostenus chichimecus, n. sp. 



9. Black; face, mouth, orbits, and broad annulus on antennae, 

 white ; collar, tegulae, line in front, spot lieneath, cuneiform mark 

 on disk of mesothorax, scutellums, spot beneath posterior wing, 

 pleura except narrow space beneath wings and anterior margin, 

 flanks of metathorax, an elongate, subtrefoil mark on posterior 

 face, base of first abdominal segment, rather broad apical and 

 narrow lateral margins of all the segments, and a dot on lateral 

 margin of second and third segments, yellowish-white ; wings 

 hyaline, apical margins narrowly dusky, nervures black ; legs 

 yellowish-white, tibiae and tarsi yellow, stripe on all the coxae, all 

 the femora above, middle tibiii3 above, four anterior tarsi and pos- 

 terior knees black ; seventh sejiment of abdomen as lona: as the 

 second, while the fourth, fifth, and sixth are very short ; the black 

 space at base of seventh segment much extended, narrowed pos- 

 teriorly, making the yellowish margin broad luterall}^ and nar- 

 row centrall}'. Densely punctured, subopacjue; metathorax ru- 

 gose, rounded, without tubercles or spines; areolet quadrate, 

 closed; abdomen densely punctured. Length 5^-7 lines. 



Orizaba; Cordova. (Sumichrast, No. 87.) 



10. Mesostenus admirandus, n. sp. 



9 Black ; face, clypeus except tip, labrum. base of mandibles, 



