THE ENTOMOLOGIST. 89 
The Mole’s Flea: a Discovery for Leap Year.—A rare 
prescience, analogous to that which led Adams and Leverrier 
to announce the existence of a ninth planet long before our 
best instruments had brought it within the range of human 
vision, induced some of our leading entomologists to name 
an insect as the Mole’s Flea, just half a century before that 
saltant hexapod vouchsafed to present himself to the 
expectant eye of science. Mr. Fitch, whose researches on 
galls and gall-insects have rendered him the facilis princeps 
of the Cecidology of this country, has discovered that the 
mole is thickly infested with a minute flea peculiar to itself. 
He writes to me thus, in reply to my request that he will 
give me some details of the capture :—“1 do not think any 
‘details of capture’ can be needed for the mole’s flea, as I 
believe the difficulty would be to find a mole on which these 
fleas were not abundant. Last spring I caught from thirty to 
forty moles, and I do not think there was one of them on 
which [ did not notice these fleas. Several of these moles 
were dead, though perhaps not stiff, when taken out of the 
ground, yet their fur contained the fleas; so I do not think 
they leave the animal so soon as is the case with some others, 
which I have observed to take their departure immediately 
after the death of the animal on which they were living. In 
killing hedgehogs, not always an easy task, I have seen the 
ground completely covered with fleas immediately afterwards : 
in one case, which | recollect more especially, the operation 
took place on a white door-step. 1 remember, last year, on 
catching a field-mouse, directly | had put an end to its 
existence by squeezing its throat, the fleas made their exit 
over my hand. If you recollect, | told you these fleas were 
blind; and I believe this fact is well known to microscopists.” 
I see by a list of microscopic objects, obligingly lent me by 
Mr. Fitch, that a “ mole’s flea without eyes” is advertised for 
sale; the price is one shilling and upwards for these and 
other parasites in the same catalogue, Mr. Fitch has supplied 
me most liberally with specimens of this flea, and L have 
forwarded a series of them to my friend Dr. Bowerbank, who 
has immortalised himself by revealing the secrets of the 
insect-wo1ld and of sponges. Dr, Bowerbank writes as 
follows :— | have carefully examined the mole’s fleas with a 
power of 200 linear, viewing them in every possible position, 
N 
