132 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol 5 



mosquito fauna is rich and includes about 125 species representing all 

 the genera typical of tropical America. The seasonal incidence of 

 ^any species is but slightly marked, breeding continues throughout 

 the year and is only relatively reduced in the height of the dry season. 

 In fact in some locahties and with certain species, it actually increases 

 at that time, for water courses and rivers which during the rains, by 

 reason of rapid current and proneness to floods, offer no opportunities 

 for mosquito propagation, become during the dry season a succession 

 of pools or long reaches of stagnant water in which Anopheles and Culex 

 species fairly riot in their abundance and, unless checked, are a serious 

 menace to the population of the vicinity. Estivation, at least as 

 regards most species and especially those of economic importance, 

 seems not to occur as oviposition takes place whenever opportunity 

 in the shape of water is to be found. Economically important species 

 are abundant, including at least nine species of Anopheles, the nearly 

 cosmopolitan Stegomyia calopus and Culex quinque-fasciatus, and other 

 species which are abundant and annoying pests. Only a few of these 

 are of known pathogenic habits, but all except the most retiring of the 

 sylvan species have to be reckoned with by the sanitarian and included 

 in the programme of control. 



The range of habits in the species is wide and extremes in specializa- 

 tion of form and habit are seen, especially among the sylvan species. 

 Many are restricted to a certain type of breeding place, the water- 

 bearing flowers of a certain genus of plants, or even to those of a single 

 species. Others among the sabethines and culicines are less exacting 

 and are to be found beyond the strict confines of the bush, will breed 

 in artificial containers, and are occasionally to be found in the adult 

 state about houses, if the latter are in reasonable proximity to their 

 breeding places. 



In connection with specialization or restriction of habit should be 

 mentioned Stegomyia calopus. This mosquito is intensely domestic, 

 is never found, except by accident, away from the immediate neighbor- 

 hood of man's habitations, and will breed only in such artificial vessels 

 or situations as it there finds. This rule is absolute and I know of no 

 exceptions thereto having occurred. I have known this mosquito to 

 breed in water-filled hollows in trees standing beside inhabited dwell- 

 ings, these fining the same role as the artificial container, but never in 

 ground water of any description. These habits entail a line of control 

 work, totally different from that employed against Anopheles, the 

 details of both classes of work I will discuss later. 



Anopheles albi^nanus, among pathogenic species, is by far the most 

 important, under present conditions, not excepting Stegomyia calopus. 

 Not only is it the most abundant of the Isthmian species of the 



