106 BRISTLE-TAILS AND SPRING-TAILS. 
and maxille disappear.” Our common white Lipura is the Euro- , 
pean L. fimetaria Linn. (fig. 38, copied from Lubbock). The 
site of the spring is indicated by an oval scar. 
Fig. 39 represents a common species of Anura found under 
stones between tide marks at Nantucket. Compared with Acho- 
rutes, the body is rather longer and slenderer and more hairy, while 
the front of the head is much prolonged, almost forming a beak. 
The legs (fig. 40) end in a large, long, curved claw. On examin- 
Fig. 36. Fig. 37. Fig. 38. 
f Y 
a 
e 
Bo 
Achorutes, Lipura fimetaria. 
ing specimens soaked in potash, I have found that the mouth-parts 
(fig. 41, md, mandibles ; ma, maxille ; e, eyes, and a singular ac- 
cessory group of small cells, which have not been noticed hereto- 
fore as far as I am aware) are exactly like those of Achorutes and 
Lipura. The mandibles, like those of other Poduras, end in from 
three to six teeth, and have a broad, many-toothed molar surface 
below. The maxillæ end in a tridentate lacinia as usual, though 
the palpi and galea I have not yet studied. 
For the reason that I can find no valid characters for sopis 
ting these two genera as a family from the other Poduras, I am in- 
clined to think that they form, by the absence of the spring, only 
a sub-division (perhaps a sub-family) of the Poduridæ. 
The best way to collect Poduras is, on turning up the stick or 
stone on the under side of which they live, to place a vial over 
them, allowing them to leap into it; they may be incited to 
