ACHORUTES. 



177 



Isotoma bicolor, "Gay. 



Podura hicolor, Q^ay. Jour. Acad. Pliiladelpliia, 1821. 



" Body plumbeous ; feet with a few hairs, rather paler 

 at base ; nails small, acute ; sjpring large, white ; eyes 

 deep black. 



" Length from one tenth to three twentieths of an 

 inch. 



" Cabinet of the Academy. 



" Our most common species, under stones, &c." 



PODURID^. 



Body cylindrica,l. The appendages of the fourth 

 abdominal segment developed into a saltatory appa- 

 ratus. 



"this family closely resembles, and has hitherto been 

 united with, the preceding. Previous writers, how- 

 ever, have not observed, or rather have not appre- 

 ciated the importance of the fact, that the saltatory 

 apparatus in this family is not homologous with that 

 of the preceding. The sub-abdominal appendage con- 

 stituting the saltatorial apparatus of the DEGEEEiAD^i is 

 as completely absent in the Podurid^ as in the LiPURiDiE, 

 but in the former family it is replaced by a similar 

 apparatus representing the corresponding appendage 

 of the fourth abdominal seg-ment. 



AcHORUTES, Templeton. 



Body cylindrical. Segments subequal. Eyes eight 

 on each side. Antennae short, 4-jointed. Feet 

 biunguiculate. No scales or clubbed hairs. Saltatory 

 appendage short. 



12 



