12 



Merida this mosquito, as well as Culexfatigans, is still very common. 

 If this difference is confirmed during the rainy season, it is undoubtedly 

 due to the existence in Vera Cruz of a pipe-borne water supply, the 

 absence of which in Merida makes it impossible to abolish the 

 innumerable water tanks in which S. fasciata breeds and which it is 

 exceedingly difficult to keep mosquito-proof. A high death rate still 

 prevails in Vera Cruz and Merida, but mosquito-borne diseases cannot 

 be held responsible. A large number of deaths are still, however, 

 returned as due to malaria, either owing to the introduction of cases 

 from the interior or to incorrect diagnosis. 



Yellow Fever Reports : Screening of ships. — Yelloiv Fev. Bur. Bull, 

 Liverpool, iii, no. 3, 30th September 1914, pp. 179-183. 



Engeland has stated that ordinary mosquito gauze is better than 

 wire gauze for screening [see this Review, Ser. B, ii, pp. 1-2], but 

 evidently an inferior quality of the latter was used. Melville-Davison 

 found that gauze manufactured of oxidised phosphor-bronze stands 

 the sea-air admirably, and this has since been confirmed. The mesh 

 opening must also be considerably less than the 2 mm. maximum 

 allowed by Engeland. In the Booth liners, brass rims are used, which 

 fit closely into the port-holes and need not be removed in order to 

 close the ports. The good results obtained on these ships have not 

 been due to comparatively small danger of infection, for the system 

 has been in force for five years, during which time numbers of cases 

 of yellow fever have occurred in the towns of Para and Manaos. For 

 a steamer to go to San Antonio, the terminus of the new Madeira- 

 Mamore Railway, and return without a certain number of cases of 

 malaria was unknown, but the first ship to use the system made two 

 voyages to San Antonio without a single case occurring. The crew 

 were permanent servants of the company, and were kept under 

 observation for some time subsequently without showing the slightest 

 signs of malaria. There is no reason why as good or even better 

 results should not be obtained by the screening of ships as those 

 obtained on shore. 



SsroELiN (H.) & SuMMERS-CoNNAL (S.). Notcs upoH the Biology of 



Stegomyia fasciata. — Yellow Fev. Bur. Bull, Liverpool, iii, no. 3, 

 30th September 1914, pp. 187-192. 



Marchoux and Simond concluded that the young females of 

 S. fasciata, when sucking blood for the first time, bite indiscriminately 

 by day and also at night, but later only during the hours of twihght. 

 This was the suggested explanation of the apparently contradictory 

 observations that yellow fever is transmitted at night only, while the 

 female S. fasciata bites at any time. As a result of experiment the 

 authors confirm the latter statement, but think that the view that 

 yellow fever is not transmitted during the day is probably incorrect. 



In connection with other experimental work it was found that 

 mosquito larvae reared in distilled water on sterilised food throve 

 and developed into adults. 



