190 



and it was feared that the native Stegomyia might become 

 infected. No further cases occurred. Reference is made also to cases 

 of yellow fever on the Gold Coast in 1911 and the anti-mosquito 

 measures adopted, but in March 1913, Lady CHfFord, the wife of the 

 Governor, his aide-camp and five natives were attacked by the disease. 

 Three cases of yellow fever amongst Europeans occurred in May 

 1912 near Abomey in Dahomey, and a number of other suspicious.cases 

 both amongst Europeans and natives having occurred, stringent 

 measures were taken for the destruction of mosquitos. 



Strickland (C). The Biology of Ceratophylhis fasciafus, Bosc, the 

 Common Rat-Flea of Great Britain. — 42nd Ann. Rept. Local Govt. 

 BcL, 1912-13; Supplement containing the Report of the Medical 

 Officer, [Cd. 7181], Appendix B., no. 5, pp. 401-412. 



This paper deals with the life-cycle of the rat flea and the conditions 

 which influence the duration of the various stages of its life. In the 

 conclusions given, the word " rubbish " is to be understood to mean 

 refuse from rat cages consisting mainly of dried grain, excreta, gravel, 

 straw, etc., which was found to be a good material for facilitating 

 the breeding of larvae. The duration of the various stages is very 

 variable even under the same conditions, temperature and humidity 

 having the most influence. On an average, the egg hatches in 5-14 

 days, an increase of humidity having a retarding, and a moderately 

 high temperature a slight accelerating effect. The larva is soon 

 killed by a high temperature (70° F.) combined with a low degree of 

 humidity (40 per cent.) However, under these conditions, the larvae 

 will live longer if rubbish be present, for they are then able to bury 

 themselves in it and thus obtain a certain amount of moisture. The 

 pupal stage is much prolonged by cold, partly due to the non- 

 emergence of the imago even when it is fully formed. The imago, 

 at least when unfed, dies much more quickly in summer than in winter. 

 Eggs are laid by the imago even at comparatively low temperatures 

 (50° F.). The larvae and imagines like to bury themselves in rubbish, 

 and in these circumstances their duration of hfe is much pro- 

 longed, even when other external conditions are somewhat severe. 

 When sexually mature the imago frequently lives at least two months, 

 but will not copulate unless it obtains rat's blood. It feeds readily 

 on man and many other animals, but will not copulate after feeding 

 on these facultative hosts, even though at least one of them — man — 

 seems to be more attractive to it than its normal host, the rat. 

 Oviposition invariably takes place within 24 hours of copulation, 

 even when the insect has only been fed once after being starved for a 

 period of many weeks. The rat's blood, therefore, probably contains 

 some substance that possesses a stimulating effect on the flea's sexual 

 organs. When starved, the imago will live for a very long time — at 

 least 17 months — but only in the presence of rubbish in which it can 

 bury itself. In the absence of rubbish the flea will only live for about 

 a month, even under the most favourable conditions of temperature 

 and humidity. It is therefore clear that the presence of rubbish 

 containing organic matter is essential for the development of the 

 flea. 



