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XI.— ON THE PEESENCE OE TWO SPEEMATHECx^ IN 

 THE EAEE MOLE FLEA (HYSTEICHOPSYLLA 

 TALP^), AND THE FLEA AS DISTEIBUTOE 

 OF A TYEOGLYPHID. 



By F. Maktin Duncan, F.E.M.S., F.E.P.S., F.Z.S. 



One Plate and Theee Text-Figures. 



(Read April 20, 1921.) 



HystrichopsyJla talpie is one of the largest known fleas. It is 

 found parasitic on the mole, occasionally on field voles, but is by 

 no means a common insect on either host, and presents several 

 points of interest. Externally this flea presents a remarkable 

 appearance, for it has a denser covering of spines and bristles than 

 is found on any other species. The colour of both sexes is a fine 

 chestnut brown, and the males average 3-5 mm. in length, while 

 females attain a length of 5 to nearly 6 mm. 



Curtis first described this flea (British Entomology, vii. p. 114) 

 in 1826, from a specimen taken by Dr. Leach in Battersea Fields, 

 and called it Fulcx talpse. This specimen, I believe, is still to be 

 seen in the National Collection at the British Museum (Natural 

 History), South Kensington. Eitsema found it in the nests of tlie 

 bee Boriibus subterranevs, and described it under the name Pvh.r, 

 ohtusiceps. As field voles are known to rob the nests of this bee, 

 it is probable that ihe fleas are carried there by these rodents. 

 Species of Hystriclioi^sylla are recorded from various parts of tlie 

 world ; H. dipiyici Eothschild having been obtained from British 

 Columbia and Alberta, the hosts being Pittorius loagicmulatus and 

 Lutreola cnergumenos. In Italy and Switzerland H. narhili has 

 been recorded as being found on Microtns nivalis ;. while from 

 Eome H. tripectinata tirahoschi is recorded as having been found 

 on the common mouse {Mus muscuh(s). Lastly, IT. talpc'e, the 

 subject of the present note, is recorded from Great Britain, Sweden, 

 Holland, Germany, Belgium, and France, on the common mole 

 and field vole. 



Although the general external characteristics of Ily.strichojJSi/Ua 

 talptm have been described by several authors, its internal anatomy 

 does not appear to have received the same attention, hence the 

 reason for what must be considered a very remarkable and im- 

 portant feature having apparently been so long overlooked. Some 

 little time ago, a fine female soecimen of this flea came into mv 

 possession, and on examining it under the microscope with an 



