71 



rats harbouring S. icterohaemorrhagiae in the kidney, they were present 

 without exception, and therefore the extermination of rats and field 

 mice is a highly important prophylactic measure against Weil's 

 disease. The chemical composition of the soil and water plays an 

 important part in the development of S. icterohaemorrhagiae and 

 consequently in the spread of the disease of which it is the causal 

 agent. 



Bodkin (G. E.). The Biology of Amblyomma dissimile, Koch, with 

 an Account of its Power of Reproducing Parthenogeneticaliy. — 



Parasitology, Cambridge, xi, no. 1, November 1918, pp. 10-17, 2 

 plates, 1 fig. 



Amhlyomma dissimile is a well known tick in British Guiana, the 

 engorged females being found on the head of Bufo marmus (bull-frog) 

 attached immediately between the eyes. The parasite is only of 

 indirect and very small economic importance, its attachment sometimes 

 resulting in the death of the host, which is a great insect-eater. 



The hosts of this tick are toads, iguanas, lizards and several species 

 of snakes, and probably the adult females are capable of engorging 

 on most cold-blooded animals, but not on warm-blooded ones, though 

 the larvae and nymphs can do so. 



The total life-cycle of A. dissimile, provided that each stage promptly 

 finds a host, takes about 153 days, but under natural conditions this 

 period must be very greatly lengthened. In the laboratory oviposition 

 proceeded regularly for about 16 days. One unfertilised female 

 tick lived 496 days and laid fertile eggs. In nature both sexes occur 

 together on the same host, the examination of 30 infested toads yielding 

 46 males and 9 females. In the laboratory four generations were 

 raised parthenogeneticaliy from two original females, no diminution 

 either in size or vigour being noticed, the results showing that such 

 generations consist entirely of females, while fertilisation results in 

 the production of a small percentage of males. 



Graham-Smith (G. S.). Hibernation of Flies in a Lincolnshire House. 



— Parasitology, Cambridge, xi, no. 1, November 1918, pp. 81-82. 



Towards the end of October 1917 a large and very old house near 

 Boston, Lincolnshire, was found to be very heavily infested with 

 hibernating flies, the window frames, after fumigation and removal 

 of the window sashes yielding as much as a bucketful of dead flies 

 from a single window. Coccinellids were also present in large numbers. 

 Early in November the window frames were fumigated with hydro- 

 cyanic acid gas, and all the joints and cracks were syringed first with 

 carbon bisulphide and then with a saturated solution of crude naph- 

 thaline in methylated spirit. No flies were seen for a few days, but 

 by the beginning of December they were as numerous as ever. A 

 second treatment and fumigation took place in December and an 

 examination in January revealed no living flies. It was stated that 

 the trouble has recurred every winter for the past 24 years, the flies 

 appearing towards the end of July and suddenly disappearing about 

 April. 



The following insects were represented : — ^Diptera, Musca autum- 

 nalis (corvina), Pollenia rudis, Pyrellia eriojjhthalma, Limnophora 



(C661) a2 



