THli ENTOMOLOGIST. 89 



The Mole's Flea : a Discoveri/ for Leap Year. — A rave 

 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 1 caught from thirty to 

 forty moles, and 1 do not think there was one of them on 

 which I 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 1 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 I recollect more especially, the operation 

 took place on a white door-step. I remember, last 3'ear, on 

 catching a field-mouse, directly 1 had put an end to its 

 existence by squeezing its throat, the fleas made their exit 

 over my hand. If you recollect, 1 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 I have 

 forwarded a series of them to my friend Dr. Bowerbank, who 

 has immortalised himself by revealing the secrets of the 

 insect-woild and of sponges. Dr. Bowerbank writes as 

 follows : — " 1 have carefully examined the mule's fleas with a 

 power of 200 linear, viewing them in every possible position, 



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