OF NATURAL HISTORY. 7H 



Body rufous, tinged with yellowish : head black on the vertex : 

 antennae blackish, excepting the two or three basal joints ; about 

 as long as the body : mandibles black at tip : thorax somewhat 

 trilobate, black, with an obsolete rufous central spot : scutel 

 black : wings hyaline ; nervures and robust carpus black ; second 

 cubital cellule confluent with the third ; inferior discoidal cellule 

 half as large as the central one : posterior tibiae dusky except at 

 base : coxse yellowish : abdomen oblong subovate, short, dusky 

 at tip ; densely punctured, with three segments, decreasing in 

 length ; a small, almost concealed terminal segment. 



Length % one-fifth of an inch. [260] 



The cubital cellules are but two, the second transverse nervure 

 being entirely wanting, and the nervure forming the anal side of 

 the cubital cellules is very slender ; the other nervures being 

 quite robust. If the genera throughout this order, are not to be 

 divided as in the Ttnthredinetse, I would propose the separation 

 of this and the following species, under the generic name of 

 Aliolus. 



The character of the abdomen agrees with this genus ; but the 

 neuration of the wings seems to agree rather better with Micro- 

 gaster. 



20. B. THORACicus. — Black; thorax and feet honey-yellow. 



Inhabits Indiana. 



J Head : thorax honey-yellow, with two oblique, 



lineated grooves ; suture before the scutel much dilated and pro- 

 found : wings hyaliue ; radial cellule with the nervures as dis- 

 tinct as the others, regularly arcuated, without any angulation ; 

 second cubital cellule much dilated and destitute of the exterior 

 nervure: metathorax black: abdomen minutely punctured or 

 lineated at base, polished towards the tip, oval ; second incisure 

 indistinct : oviduct longer than the abdomen : feet honey-yellow. 



Length less than one-tenth of an inch. 



MICIIOGASTER Latr. 



1. M. ENSIGER.— Black ; feet and each side of the base of the 

 abdomen yellowish. 



Inhabits Indiana. 



9 Body black, with dilated punctures and minute hairs : moutli 

 honey-yellow: palpi white: thorax with a yellow wing-scale ; 

 1835.] 



