1865.] 291 



oblique ; parallel nervure not intersticial ; nervures of the posterior 



wing robust. Legs short and robust ; coxae small, the posterior pair 

 compressed or somewhat twisted. Abdomen subsessile, short, broadly 

 ovate in 9 , less broad in £ . depressed ; apex in 9 subcompressed, the 

 ovipositor subexserted, the ventral valve large, and shaped somewhat 

 like a plow-share. 



This genus has much the general appearance of certain Tenthredini- 

 dous genera, by means of the short, robust form, the large, broad wings 

 and the nearly sessile abdomen. It belongs to the Polymorphes of 

 Wesmael, but T am unable to identify it with any of the genera described 

 in that division. The marginal and second and third submarginal cells of 

 the anterior wings are indistinctly defined, the nervures being subob- 

 solete. 



I notice in the Society's Collection, two or three species from the 



Atlantic States, which belongs to this genus; all have dark fuscous 



wings, and the body of one species is entirely black; the others are 



similarly colored to the following. 



Tenthredoides seminiger. n. sp. 



Yellowish-red, shining ; head, antennae, breast, metathorox, coxeb and tro- 

 chanters, black : wings blackish-fuscous ; metathorax coarsely rugose. 



Female. — Head black, smooth and polished, slightly pubescent ; nar- 

 row inner and broad outer orbits, and the basal margin of the clypeus. 

 rufous; antennae entirely black. Thorax yellowish-red, smooth and 

 polished ; mesothorax with two approximate black dots, sometimes con- 

 fluent, on the extreme anterior margin, sometimes concealed by the 

 head ; pectus, and the pleura except the broad aDterior margin, black ; 

 space on each side of the scutellum obliquely striated, its lower margin 

 flat, polished and black, as well as the space on each side of the post- 

 scutellum ; metathorax black, opaque, coarsely rugose, the disk having 

 a longitudinal ovate excavation, surrounded by a well-defined carina ; 

 tegulae yellowish-red, bordered behind with black. Wings uniform 

 blackish-fuscous ; nervures black; lower margin of the first submarginal 

 cell, two dots at tip of prrediscoidal cell, and a furcate line at tip of 

 second submarginal cell where it joins the marginal, hyaline. Legs 

 yellowish-red, the coxae and trochanters black, the four posterior tarsi, 

 and tips of the posterior femora within, more or less dusky. Abdomen 

 about as long as the thorax, broadly ovate, depressed, polished, yellow- 

 ish-red, basal segment orange-yellow, with a more or less distinct black 

 mark on the prominent dorsal middle; valves of the ovipositor robust, 

 black. Length ol lines; expanse of wings 8 lines. 



Male. — Resembles the female, but the antennae are as long as the 



