A SUPPOSED NEW FLEA. 
31 
FIG. I. 
prothorax suggest affinity to Ceratopsyllus, as do the finely but 
distinctly serrate claws. The position of the 
stigmata is so distinctly different, however, that 
this flea may eventually be placed elsewhere, 
although it may tentatively, at least, rest in the 
genus already erected. 
This flea, apparently undescribed heretofore, was obtained in 
large numbers from a mole secured by Mr. Edward H. Fogg in 
February last. Its life history has not been worked out, but 
from the known habits of allied species it may be assumed that 
the larval stage is passed in the nest of its host. Its structure 
affords a striking illustration of adaptation through selection. . 
The mole, covered with hair so fine that it may be described as 
fur, passes its life for the most part beneath the surface of the 
ground, burrowing almost constantly for food, hurrying back 
and forth at surprising speed in its subterranean tunnels. It is 
evident that a flea, in order to remain upon its host under such 
conditions, must possess claws specially adapted to grasping; 
it must literally cling for life by tooth and nail, and we find the 
cleft, finely serrated claws even more distinctly developed than 
in the flea which infests the dog and cat, Ceratopsyllus serraticeps, 
shown in Figure i. It is also smaller by rather more than one 
third, and its cape of strong spines on the prothorax lies more 
closely to the body. It is probably blind, as its 
small eyes, under high magnifying power, appear 
to be rudimentary, and are indistinctly defined as 
to contour. The under side of the feet are 
densely covered with pits which are undoubtedly 
sense organs. Thus equipped with organs of touch and with 
claws adapted to grasping the tiniest single hair, the 
mole flea continues to maintain itself with more or 
less success in what must be a precarious if not un¬ 
comfortable situation. Figure 2 is a good represent¬ 
ation of the flea, and Figure 3 shows the thumb and 
fig. 3. finger like structure of the claw, all being highly 
magnified. Undoubtedly development is still going forward; 
the many fall and perish ; the few cling successfully and survive. 
fig. 2. 
