1915.] 75 



a short spiniform bristle iiear the apex and anotlier on the proximal 

 portion of the horizontal arm, besides numerous thin hairs. 



$ . Seventh sternite with a shallow sinus, the lobe above the sinus 

 projecting a little more than the ventral lobe (fig. 50). Eighth tergite 

 with four or five bristles below the stigma, the latter of normal size. 

 Stylet three times as long as it is broad at the base, upper lateral 

 bristle absent. Head of receptaculum seminis about half as long 

 again as it is broad, and much longer and wider than the tail. 



A common species in England and Scotland ; not recorded from 

 Ireland. Has been found on many hosts ; among them may be cited 

 the bank vole (Evotomys glareolvs), the Orkney vole (Microtus 

 or cade lis I a), the long- tailed field mouse (Ajjodemus fylvaticus), the 

 dormouse (Muscardinus av eUanarms), and the stosit {Mustela erminea) . 



24. Ceratophyllus walkeri Roths. (1902). 



(Figs. 51, 52). 



Very dark, nearly black. Occiput usually with median row of 

 four bristles. Stigmata larger than in the previously named mammal 

 fleas, that of eighth tergite wider than foretibia. Upper and lower 

 antepygidial bristles equal in length, in ^ quite small, in ? one-third 

 as long as the central bristle. 



(^ . First midtarsal segment with several long thin bristles, the 

 apical one reaching a little beyond the second segment. Apical margin 

 of eighth tergite subdorsally straight, slightly incurved, and strongly 

 slanting, bearing here four long bristles and being excised subventrally. 

 Eighth sternite (fig. 51) similar to that of mustelae, slightly broader 

 apically, the upper angle of the widened proximal portion directed 

 upwards. Process P of the clasper long, narrow ; the finger broad, 

 the posterior margin being widened before the middle, where it bears 

 a stout bristle pointing downward, and again at the apex, where it 

 bears two short, stout and obtuse bristles. 



$ . Seventh sternite (fig. 52) very deeply sinuate, both lobes being 

 narrow, apex of the upper one more or less rounded off, and of the lower 

 one pointed. Eighth tergite with two long bristles below the stigma. 

 Stylet three times as long as it is broad, both lateral bristles long. 

 Head of receptaculum seminis more than twice as long as it is broad, 

 and much longer than the tail, which is only half the width of the head. 



A common species in England and Scotland, not recorded from 



