64 



The cocoon affords protection against drought and also against exces- 

 sive moisture, as was shown by experiments in which cocoons were 

 immersed in water for 12 hours and survived. 



On adults, experiments were made to ascertain the duration of life 

 when fed and unfed. At 45°-50° F., with nearly saturated air, fleas 

 can live for many days unfed, specimens of P. irritans surviving for 

 125 days and Ceratophyllus gallinae for 127 days. However, under 

 only moderately unfavourable conditions of temperature and humidit}' 

 the powers of endurance are but slight in the absence of food. In 

 a box, if fed on their natural host, P. irritans may live for upwards 

 of 513 days, C.fasciatus for 106 days and X. cheopis, fed on man, 100 

 days. C. canis and C. gallinae have lived for 234 and 345 days when fed 

 on man. The author is of the opinion that feeding on warm-blooded 

 animals is essential to reproduction in this insect. In these experi- 

 ments no support has been obtained for the theory that flea breeding 

 can take place in the absence of an animal host to provide food for 

 the adult, and there was no evidence that the amount of food taken 

 had any influence on the fertility of the eggs laid, but only upon the 

 number. As a result of these experiments it is shown that, taking 

 its different stages into account, a flea may survive for very long 

 periods without a host being present — for example, C. fascial us for 

 22 months, P. irritans for 19 months, A', cheopis 10 months, C canis 

 18 months and C gallinae 12 months. 



Eeid (H. a.). Bots. Their Natural Powers of Resistance. — Jl. Aqric, 



Wellington, N. Z., viii, no . 1, 20th Jan. 1914, p. 53. 



On 24th November the writer received two specimens of bots taken 

 from the nasal cavities of a sheep. These had been placed in a bottle 

 with 2 per cent, formalin solution two days previously and when 

 received one was found to be still alive. They proved to be larvae of 

 Oestrus ovis. The bot was kept in this solution and found to be still 

 alive up till 28th November. This observation serv^es to illustrate 

 how ineffectual is the administration of drugs destined to destroy these 

 parasites during the life of their host. [To be effective the drugs 

 must be administered in a liquid having a very feeble surface tension, 

 so that it can penetrate the specially protected tracheal system of 

 the larvae ; for the value of bile in this connexion, cf. Bull. Ent. 

 Research, i, 1910, p. 229.— Ed.] 



Wenyon (C. M.). Kala-Azar in Malta, with some Remarks on the 

 various Leishmaniases. -Trans. Soc. Trop.Med. Hyg., London, vii, 

 no. 3, Jan. 1914, pp. 97-118, 1 pi. 



The author in this paper first of all brings to notice observation.s 

 he made on kala-azar in Malta. Comparing these with observation.s 

 made in India, North Africa, Italy, Sicily, Greece and China, he con- 

 cludes that in all the localities the disease is identical. As to the (jues- 

 tion of the etiology of the disease, there is still much doubt as to the 

 mode of transmission. Basile in Europe, and the Sergents, L'Heritier 

 and Lemaire in North Africa, have carried out experiments in which 

 they caused fleas from infected dogs to feed on dogs assumed to be 

 free from disease after examination of the liver by puncture. The 



