103 



*' uestling' " rats were of this species, wliile of the ileus taken 

 from rats found dead, either of injury or disease, about 90 per 

 cent, were C. fasciatus. From this it appears that fasciatus 

 deserts a dead rat later than do other species. No correlation 

 was discovered between the sporadic cases of rat plague and the 

 average number of C. fasciatus per rat. Altogether 1,986 speci- 

 mens of C. fasciatus were obtained, of which 68 per cent, came 

 from outhouses, &c., and 32 per cent, from the fields; this is in 

 striking contrast with Ctenophthalmus agyrtes. The flea was 

 also found on the following hosts: — man, stoat, mouse, ferret, 

 and rabbit. In India this species can transmit plague from rat 

 to rat (JIus rattus). 



Cteiiophthalvius agyrtes. — The rat appears to be the true host 

 of this species, but it was also found on the stoat and ferret. The 

 average per rat was 1"5 per cent., and no correlation was found 

 between the presence of plague in rats in certain districts and the 

 average number of C. agyrtes. Thirty-five of these fleas were 

 taken from "nestling" rats (about 30 per cent.), while only 

 five were taken from about 30 rats, dead of injury or disease. 

 Possibly they leave their host very rapidly after its death. The 

 seasonal variation of C. agyrtes apparently depends on tempera- 

 ture and moisture. It is a "country" flea, for 61 per cent, 

 came from hedgerows and 39 per cent, from buildings. This 

 species does not bite man, and its significance therefore is 

 restricted to the possibility of its transmitting and keeping up 

 plague infection from rat to rat. 



The other species of fleas found on the rats were: — Ceratopliyllus 

 mustelae (IT), C. walkeri (8), C. gallinae (2), C. hirundinis (1), 

 Archaeopsylla eririacei (7), Ctenopsylla viusculi (3), Ctenoph- 

 thalmus pentacanthiis (3), C. bisoctodentatus (4), Pulex irritans 

 (2), Hystrichopsylla talpae (3), Ctenocephalus canis (2), Palaeo- 

 psylla soricis (1), and P. minor (1). Probably all these species 

 had only an accidental connection with the rats, though it is 

 possible that some of them might become important under other 

 conditions. 



Although only five rats were found with lice, it is interesting 

 to note that many of the rodents were infected w^ith Trypanosoina 

 leioisi. Three females of Ixodes temiirostris were found for the 

 first time on rats, their usual hosts being shrews, voles, and 

 harvest mice. Haemogamasus liirsutus commonly occurring in 

 moles' nests, Gamasus coleoptratorum, G. terribilis,aiLid Notoedres 

 sp. (the cause of ear scabies) were also found, together with 

 Haematopinus spimdosus and Haematopinus sp? 



!N'tjttall (G. H. F.) & Strickland (C). Report on rat fleas in 

 Cambridgeshire. — Parasitology, vi, no. 1, April 1913, pp. 

 18-19. Republished from the Forty-first Annual Report of 

 the Local Govt. Board, 1911-12. 



The record relates to fleas collected from rats in and about 

 Cambridge during the period from 3rd March 1909 to 20th 

 November 1911. 



H0167 A 2 



