Jheringula paulensis, a new generic Type of Macrothricidæ. 7 



the present species will be easily distinguished from any 

 new species that may hereafter be discovered. The specific 

 name here proposed refers to the place where this form has 

 up to the present been stated to occur (Sao Paulo). 



Description of the Partheiiogeiietic Female. 



The length of fully grown specimens amounts to about 

 one and a half millimetres; but under favourable cir- 

 cumstances they may grow somewhat beyond this size. The 

 largest specimen I have observed, had a length of 1.64 mm, 

 and this seems indeed to be the maximum size of the species. 

 On the other hand, ovigerous specimens are found, which 

 scarcely exceed one millimeter in length. 



The general form of the body (see PL, 1 figs. 1 & 2) is 

 rather short and clumsy, somewhat recalling that in 

 Macrothrix. It is at once distinguished, however, from 

 that in the said genus by the very distinct and deep dorsal 

 depression defining the cephalic part above from the cara- 

 pace. The latter is comparatively short, so that is does not 

 completely cover the body proper, the hindmost part of which, 

 adjoining the tail, is constantly exposed beyond its posterior 

 edges. Seen laterally (^fig. 1), it appears irregularly quadran- 

 gular in form, with the lieight fully as great as the length. 

 Its upper margin is but slightly convex, and terminates be- 

 hind in a nearly rectangular comer. The lower margin is 

 more curved, forming in the middle an abrupt bend, and 

 joining, without any intervening angle, the posterior margin, 

 which is almost transversely truncated. Anteriorly, the free 

 edges of the valves ascend vertically to the point where 



