40 



numerous, several hundreds being bred out, although they had not 

 been found in the creek during the monsoon. This mosquito was 

 twice found by the author to be infected with malarial parasites during 

 the monsoon. 



The larvae of A. fuliginosus were found throughout the year, 

 especially in the main canal and to a less extent in deep permanent 

 weedy pools ; they were found also in the Bela. This mosquito did 

 not show any real increase relative to the other species during the fever 

 season (July to middle of November), but towards the end of Novem- 

 ber its numbers increased enormously. It is essentially a cold weather 

 mosquito, though present all the year round. It was never found 

 infected with malaria parasites. 



, The remaining mosquitos were all common in the district, but their 

 numbers were not considered sufficient to be of any importance with 

 regard to the spread of malaria. They include : — A. 'pulcherrimus, 

 A.fowleri, A. listoni, A. turkhudi, A. harhirostris (which seems to have 

 largely disappeared with the clearing of the thick scrub jungle from 

 the Bela in 1911), A. sinensis {nigerrimus), A. maculipennis, and 

 A. jamesii (not found by the author, recorded by Colonel Adie 

 in 1910). 



The extraordinarily small numbers of adult Cuhcine mosquitos which 

 were found during the fever season in villages, and even in the city, 

 was remarkable. During the early spring there is an enormous increase 

 in these mosquitos, commencing at the end of March, reaching its 

 greatest height in April, and d)dng away in May. The rise in the 

 prevalence of Anopheline mosquitos commences rather later in the 

 year. This begins in April, is at its greatest height during the first 

 fortnight in May, and dies away again in June. There is a second 

 rise in the Anophelines to a much higher level than in the spring, when 

 the rains break. The Culicines do not show this second rise, and in 

 the author's opinion, the fall in the number of Anophehnes during 

 June is solely due to want of breeding grounds during May and the 

 first half of June, owing to the drying up of all the pools. These 

 seasonal variations have been noticed in many stations in the Punjab. 

 Of Culicines, C. fatigans was present in enormous numbers in March. 

 A fair number of Mucidns scatophagoides larvae, nymphs and adults 

 was found in August and September. 



Desvoidya obturbans was also noticed. Numbers of Stegomyia were 

 present, especially in September, the commonest species being S. 

 scutdlaris and the next in order of frequency S.fasciata. They were 

 found breeding in the usual places, pots, tins, cisterns, etc., and par- 

 ticularly in the cement syphon tubes of the smaller branches of the 

 canal. They were also occasionally found in wells. 



During the fever season, Anophelines outnumbered the Culicines 

 by ten to one, but only four of the former can be regarded as important 

 in spreading malaria, viz., A. culifacies, A. sfephensi, A. fuliginosus 

 and A. rossi. The seasonal prevalence of the last-named agrees 

 exactly with that of malaria, but it has never been found carrying 

 malarial parasites in nature. A. fuliginosus is probably not an 

 important carrier. There is no relation between its prevalence and 

 that of the disease and it is most abundant when malaria is dying out. 



