278 DE VOGEL. 



Manson ° includes Myzomyia rossii in a list of anophelines "which have been 

 shown with more or less precision to be efficient hosts of the malarial parasites." 

 It is noteworthy that in the same edition Theobald, and also Giles and Donitz, 

 mention the names of Daniels, Ross, Christopher, and Stephens as having in 

 vain attempted to show the capability of infection of Myzomyia rossii; and 

 neither Theobald nor Manson gives the names of those who have been able to 

 do so. Theobald only refers to the opinion of Mr. E. Green, 10 government ento- 

 mologist at Ceylon, as to the part played by Myzomyia rossii in the epidemics 

 of malaria which break out from time to time in the Batticoloa district of 

 Ceylon. This seems to imply that he infers the infectibility from epidemiological 

 data, and not from successful experiments. From this article it appears that 

 Mr. Green has not made any experiments in transmitting the infection. 



I have never found an infected specimen among the large numbers of 

 individuals of Myzomyia rossii which I have caught and examined in my 

 own house at Samarang. 



Other Anophelinas have been met with further inland, but never near 

 the shore. Mosquito larva; floating horizontally on the surface of the 

 water have been collected in various degrees of contamination, and the 

 mosquitoes developed from these larva; resembled each other in all 

 particulars. 



In my publication "Anophelines dans l'eau de mer," 11 I called this 

 species "Anopheles vagus" from the description given by Donitz. 12 

 Specimens obtained from larva? bred in sea water and partially evaporated 

 sea water were examined by Professor De Meyero, of Amsterdam, and 

 he declared them all to be Myzomyia rossii. Indeed, Blanchard, among 

 other authorities, also considers Anopheles vagus not to be a new species 

 discovered by Donitz, but as identical with Myzomyia rossii. 



The absence of any other species which might presumably be a trans- 

 mitter of malaria led to the question whether the reason why infection 

 experiments with Myzomyia rossii had yielded negative results might not 

 be found in the fact that up to the present time they had always been 

 made with specimens bred in fresh water. Until quite recently it was 

 not known that Myzomyia rossii is able to develop in water containing a 

 high percentage of salt; the M. rossii caught in my house, which, as above 

 slated. I had examined with negative results, were also derived from 

 fresh water. This species, so frequently encountered near the seacoast, 

 generally breeds in water containing a comparatively high percentage of 

 sodium chloride. In connection with the prevalence of malaria near the ' 

 coast, this fact leads to the supposition that possibly this high percentage 

 of salt in the breeding places may offer a favorable condition for (lie 



"Tropical Diseases. New York, 4th ed. (1907), 147. 



"Trop. Ayr. (1900), 32, 84. Kindly sent me for reference by Dr. W. T. 

 Hunger, of Salatiga. 



n Atti Soc. mal. (1907), 8, 1-27. 



12 Ztschr. f. Hyg. u. Infectionskrankh. (1902), 41, 80. 



