1912. ] C. A. Patva: The Mosquitoes of Calcutta. 95 
In the early part of the survey, I did not think it necessary 
to separate the Culex with the unbanded proboscis from those with 
the banded proboscis, but later on I considered it advisable to 
keep them separate. Hence it will be seen that from March 22nd 
1910, the two forms are given as Culex A (unbanded proboscis) 
and Culex B (banded proboscis). 
The following species were bred during the twelve months of 
the survey :— 
Culex A. 
Culex B. 
Culex concolor, Desv. 
Leucomyia gelida, Theob. 
Stegomyta scutellaris, I. 
Stegomyta fasciata, Fab. 
Desvoidea obturbans, Wik., and varieties. 
Toxorhynchites tmmasericors, Wk. 
Myzomyta rossi, Giles. 
Myzomyta ludlowt, Theob. 
The area dealt with in the survey has been divided into ten 
districts which are briefly defined and described in Table I. 
Table II gives full particulars of the work done during the 
year. Each column represents a fortnight’s work ; Roman figures 
are used to indicate the districts from which the various larvae 
were brought in; and the actual number of adults that emerged 
is shown by Arabic figures in brackets. 
In the next three Tables ( III, [V and V) the breeding habits 
for the three principal seasons are compared :—vzz. the ‘‘ hot, ”’ 
‘rainy ”’ and “‘ cold’”’ seasons. 
The hot season in Calcutta generally commences early in 
March and extends at least to the end of May or the beginning of 
June. There are occasional showers of rain during this period, but 
mosquitoes do not find much stagnant water about to encourage 
the breeding of larvae. Some species however are rather common 
at this time of the year. 
The rainy season commences in June or July and ends after 
the 15th of October. At this time water is most plentiful and 
hence it is the most suitable period for the breeding of mosquito 
larvae. 
The cold season starts in November and lasts till the end of 
February at latest. ‘There is very little or no rain during this time 
and mosquitoes do not seem to be so plentiful. 
It is generally during the cold season that the Calcutta Corpo- 
ration undertakes the destruction of mosquito larvae. A more 
suitable time of the year for this kind of work would perhaps be 
the rainy season as during that time larvae are found in abund- 
ance in all kinds of situations, and mosquitoes are most common 
then. ‘The constant rain may render it difficult to do this work 
satisfactorily however. 
