principally marine, found on the South Coast of Devonshire. 11 
of natural subjects than elsewhere; it is not uncommon to see 
four or five together in one case of my preserved birds, and yet 
I have never observed it in any other part of my house. The 
progressive motion of this insect is very slow and uniform, con- 
tracting its arms and becoming motionless when touched. On the . 
contrary the P. acaroides, though not very quick in its usual move- 
ments, will, if touched, run either backwards or forwards with 
great celerity, and will sometimes leap like Aranea scenica ; pos- 
sibly like that insect it springs upon its prey. 
NYCTERIBIA. 
Without eyes, antenne, or anterior mouth, but upon the top of 
the thorax a cylindric proboscis or sucker: legs six, each armed 
with two hooked claws. 
NYCTERIBIA VESPERTILIONIS. 
3 u: Dass; Fig. 5. 
E 
Nyctenbus Vespertilionis. Latreille, Gen. Crust. et Insect. tom. iv. 
p. 364. tab. 15. fig. 11. ' 
Celeripes Vespertilionis. Trans. Linn. Soc. vol. ix. p. 166. note. 
This extraordinary animal, hitherto only observed to inhabit 
two species of bats, Vespertilio Ferrum-equinum and minutus, is 
properly divided into two parts, the thorax and abdomen, being 
‘destitute of head, as well as of eyes, and the other appendages 
usually attached to that part. lt has only three pairs of long 
legs, which are affixed to the thorax, and are placed in a very 
unusual manner, originating from the upper part, leaving the 
visible part of the thorax very narrow above, but consequently 
much broader beneath, and when viewed in this last position it 
obscures the first joint of the. legs; on this side there is a longi- 
tudinal suture. 2 
c2 The 
