4:08 Description of a New Genus of Trichojrterygidce, 



with the laminate processes of all the femora, and posterior 

 coxae, and the long shining hairs on the abdomen, appears 

 to be to facilitate the escape of the insect in case of alarm ; 

 with all the limbs closed up, and protected in this manner, 

 no inclined surface could arrest its downward progress. The 

 legs are short to an absolute deformity, with all the femora 

 widely laminate on their interior edge ; the tibial curved 

 outwardly, and armed on each side with numerous strong 

 spines ; the tarsi are furnished at the apex with two rather 

 long, straight setae ; the posterior coxse appear at first sight 

 to be of great size, but are, in fact, almost rudimentary, 

 nearly the whole joint consisting of an immense quadrate 

 lamina, of which the coxa itself forms only the basal and 

 interior margin ; the abdomen is furnished on all the exposed 

 segments with long, recumbent, golden setae, which extend 

 far beyond its apex in the shape of a long beard, and its 

 terminal segment is divided into two points above and three 

 below ; the intermediate of these last being much shorter 

 than the other two, and not connected with them at its 

 base. This formation strongly resembles the incised apex 

 of the abdomen, so universal in the Tachyporidae, and points 

 to the affinity existing between that family and the Tricho- 

 pterygidae ; an affinity also conspicuous in many other points 

 of their anatomy, and in their general appearance and habits. 

 Before I conclude these preliminary remarks, I must pub- 

 licly acknowledge my obligations to Dr. Le Conte for the 

 zealous assistance he has long rendered me in investigating 

 the Trichopterygidse of America. Among the species which 

 he has himself discovered there is one which will form a 

 new genus, less monstrous indeed, but quite as interesting 

 as the one I am about to describe. I would willingly have 

 included a description of this species in my present paper, 

 but am not yet able to speak with accuracy of its anatomical 

 details. 



