MYZOMYIA ROSSII AS A MALARIA CARRIER. 279 



transference of the gametes to the stomach of the mosquito and the 

 further development of the parasites, i. e., it may render the mosquito 

 more liable to malarial infection. 



Considered in this connection, the statement of Schoo, namety, that 

 in the polders of North Holland malaria formerly raged more violently 

 in those places where the water was brackish, acquires a special signifi- 

 cance. At Samarang, it appears from the morbidity tables collected by 

 Doctor Terburgh that the number of children with an enlarged spleen 

 varies between 60 and 100 per cent in the native villages (kampongs) 

 situated along the coast and the two overflow canals which carry brackish 

 water far inland and which contain innumerable pools along their banks. 

 Among the rice fields and fresh-water marshes farther in the interior, 

 the numbers vary between 5 and 25 per cent. In the quarters of the 

 town of Samarang situated farther from the coast, I have thus far found 

 only two anopheline species, chiefly Myzomyia rossii, and much more 

 rarely Myzorrliynchus barbirostris v. d. Wulp. (specimens determined by 

 Theobald). 



The larva 3 which I have encountered in the rice fields near Samarang 

 before and after the growing of the crops, as well as in fresh-water ponds 

 and marshes, invariably developed into imagines, which, as far as I could 

 observe, in every detail resembled specimens of Myzomyia rossii found 

 along the coast. I have never found Myzorrliynchus barbirostris in the 

 larval state, but always as an imago, and then very rarely. Although 

 other anopheline species may occur at Samarang, it is certain that 

 Myzomyia rossii far exceeds them in number, and forms the most im- 

 portant subject for malarial epidemiology here. Green 13 mentions that 

 Mysomyia rossii also is the species occurring in the Batticoloa district. 

 It is a remarkable fact in connection with the malaria epidemics which 

 he mentions, that, in this district also, the breeding places were found 

 along a lake containing brackish water. No other anopheline species 

 found in our Archipelago is known to adajit itself so readily to the saline 

 condition of the water in which the ova are deposited, as Myzomyia rossii}* 



13 hoc. cit. 



"I find it stated in the Iicr. of Some of the Recent Advances in Trop. Med., 

 supplement of the Third Rep. Wellcome Research Lab. at the Gordon Memorial 

 College. Khartoum, page 134, that in 1908 F. H. Foly and A. Yvernault published 

 a paper entitled "Anophelines dans d'eau salee" in the Bull. Soc. Path. Exot. 

 (190S), 1, 172, in which they say that in Algiers breeding places of the anopheline 

 species Pyrelophorus chaudoyei Theob. were found containing a high percentage 

 of salt; and in the Atti Soc. mal. (1906), 7, that in Algiers, larvae of Anopheles 

 maculipcnnis, which occurs exclusively along the shore of the Mediterranean, 

 were found in water containing 0.4S1 per cent of sodium chloride_. It is also 

 stated by Schoo that Nuttal, Celli, Ficalbi, Grassi, Centanni, Christopher and 

 Stephens found larvje in water containing 0.656 per cent sodium chloride, Perrone 

 in 1.87 per cent, and Vivanti in 1.74 per cent sodium chloride. 



