278 SPOROZOA. 



(3) Taking all-India generally, P. vtvax is the predominant 

 species, but this only appHes to the spring and early summer 

 months. In autumn and early winter L. malaria usually 

 becomes predominant. 



(4) Benign tertian {P. vivax) and quartan malaria {P. malaria) 

 are almost equally common in Ceylon, although in certain parts 

 of the island — and especially in the hilly districts — quartan 

 malaria predominates. The figure for maHgnant tertian 

 {L. malar ise) is extremely low throughout the island. 



Taking the figures for India as a whole, it is clear that 

 benign tertian and maHgnant tertian infections share the main 

 incidence of malaria in India about equally between them, 

 while quartan malaria is responsible for less than 7 per cent. 

 The relative distribution of the different species in various 

 localities will be seen from the map reproduced from Knowles, 

 Senior White, and Das-Gupta on p. 279. 



Distribution of Mosquito-carriers of Malaria. 



Covell (1931) has summarized the available information 

 concerning the mosquito carriers of malaria in India, Burma, 

 and Ceylon as follows : — 



" The chief malaria carriers in Northern and Peninsular 

 India are A . culicifacies, A . stephensi, and A . listonii. A . culici- 

 facies is the most important vector in rural areas, whilst 

 A. stephensi is notorious as being the great urban malaria 

 carrier of India, it being the only malaria- carrying species 

 capable of adapting itself to the conditions obtaining in cities. 



"A. maculatus and its variety willmori are considered to be 

 important carriers in submontane areas, chiefly on epidemio- 

 logical grounds. A. maculatus has been found naturally 

 infected (gut only) by Feegrade (1927 a) in Burma. 



' ' In Eastern India A . minimus is probably the most important 

 carrier. Ramsay (1930) has shown this species to be the 

 principal vector in the Cachar District of Assam. Iyengar 

 (1927) considers A. minimus var. varuna to be the chief 

 carrier in Lower Bengal. Sur and Sur (1929), as the 

 result of their dissections under natural conditions, conclude 

 that A. philippinensis plays an important part in malaria 

 transmission in Bengal. This species has also been found 

 naturally infected in Burma (Feegrade, 1926). A. fuliginosus 

 has also been found infected in nature in Bengal and in Madras, 

 but this species is not generally considered to play an important 

 part in transmission. 



"A. ludlowii is an important carrier in the Andamans and 

 on the coasts of Burma and Bengal. In the Andamans it is 

 considered to be the only vector of any practical importance. 



