16 



MacGregor (M. E.). The Influence of Drought upon Mosquito Life in 



Surrey. — Bull. Ent. Res., London, xii, pt. 3, November 1921, 

 pp. 205-209. 



After the unusual and prolonged drought of 1921, a survey was made 

 of the Surrey district to determine the effect of the weather on the 

 mosquito fauna. Contrary to expectation, it was found impossible 

 to obtain more than a few individuals of Anopheles maculipennis 

 (adults),/!, hifurcatus (larvae), Theohaldia {Ctilicella) morsitans (larvae, 

 pupae and adults) and Culex pipiens (larvae, pupae and adults). 

 The normal conditions of occurrence of these species and their 

 appearance under drought conditions are discussed ; other species 

 that occur in normal years, but were practically unobtainable in 1921, 

 include A. plumb eiis, Theohaldia {Ciilicella)fumipennis, Aedes {Finlaya) 

 geniculatus, A. {Ochlerotatus) caspius, A. (0.) pimcfor vslt. meigenanus 

 {0. nemorosus), A. (0.) macidatus {waterhousei) and Theohaldia 

 anmdata. 



It is evident from these records that drought tends to affect mosquitos 

 adversely, decreasing the normal breeding-places and, in the case of 

 certain species, causing them to disappear entirely. It will be interest- 

 ing to notice whether the species that practically disappeared during 

 the drought will be rare in the same area in future years. Predictions 

 were made at the beginning of the hot weather that there would 

 probably be a great increase in the number of mosquitos, which, taken 

 in conjunction with the numbers of returned ex-soldiers suffering 

 from malaria, would result in many new cases of indigenous malaria. 

 The reverse, however, has been the case, for while the number of 

 indigenous cases in 1920 was thirty-six, those recorded up to 

 29th August 1921 numbered only four. 



Dry (F. W.) . Trypanosomiasis in the Absence of Tsetses, and a Human 

 Disease possibly carried by Sinmlinm in Kenya Colony. — Btdl. 

 Ent. Res., London, xii, pt. 3, November 1921, pp. 233-238, 2 plates. 



An investigation into an outbreak of trypanosomiasis of cattle near 

 Kericho, in the Lumbwa country of Kenya Colony, in 1920 revealed 

 the presence of Trypanosoma uniforme. Ten cases were recorded before 

 the outbreak was brought to an end by the slaughter of infected animals. 

 A collection of blood-sucking flies and ticks taken in the region included 

 .Haematopota similis, Ric, H. hirta, Ric, H. brunnescens , Ric, H. 

 alluaudi, Sure, H. ngandae, Ric, Stomoxys calcitrans, L., 5. varipes, 

 Bezzi, 5. nigra, Macq., Amblyomma variegatum, F., and Boophilus 

 sp. Although there is an extensive area of thick thorn forest in the 

 Chemosit River district of the Lumbwa Reserve, which is almost 

 uninhabited owing to its being infested with Simulinm, the author's 

 enquiries revealed conclusively that this fly was not a factor in the 

 outbreak of trypanosomiasis in question. It is most likely that the 

 disease was introduced by one or more animals that were infected 

 when they arrived, and was spread by the agency of Stomoxys. 



The species of Simulium infesting the dense thorn forest has been 

 identified as 5. neavei, Roub. The flies are very active, especially 

 in the afternoon, and while they do not often trouble persons on the 

 march, or those wearing European clothes, natives at rest are almost 

 immediately attacked, especially when the sunshine is not intense. 

 Many natives in this region suffer from a skin aftection that they 



