LIFE HISTORY AND SEASONAL PREVALENCE 137 



of October, though neither they nor the two persistent 

 species of Culex, above noted, exhibit any tendency to 

 bite, so that there is no longer any need for the use of 

 Mosquito nets, whether on the score of comfort or safety, 

 for in India, just as is the case in England, we find that the 

 question as to whether or not Mosquitoes will attack human 

 beings is entirely one of air temperature. Celli says that 

 the adult Anopheles will bite as soon as it is out of the pupa 

 case, and after they have digested their meal, bite every two 

 days or so, and ovulate several times. As far as I can judge 

 by the rather desultory experiences of correspondents and 

 myself, I fancy this conveys rather too high an idea of the 

 gastronomic and reproductive capabilities of individual in- 

 sects : that they generally take some four days to renew 

 their appetite after a full feed, and that the laying of a 

 couple of batches of eggs is about the limit of the reproduc- 

 tive capabilities of most of them ; but doubtless they vary in 

 this, and their intolerance of captivity makes such matters 

 difficult of determination. However this may be, there can 

 be no doubt of the enormous capabilities of multiplication 

 possessed by the entire family, and this strongly tends 

 to neutralise any check that can be imposed upon it by 

 natural enemies. 



Like the larvae, the adult insects may be roughly classi- 

 fied as domestic, field, and jungle species ; and they gener- 

 ally agree in these respects with the corresponding larvse, 

 though Celli emphatically states than An. 7naculipennis is 

 domestic, while An. bifurcatiis is a field insect ; whereas 

 Ficalbi regards the habits of their larvae as the reverse. 

 It is impossible, however, to make distinctions of a rigid 

 character in such matters, and the looser our conceptions of 

 their signification, the better, though they are very useful 

 for general purposes if employed with such reservations. 

 Although some few species are active throughout the day, 

 e.g., An. bifurcatiis, in Italy, taken as a family, gnats are 

 essentially nocturnal, and especially crepuscular insects. 

 Speaking generally. Mosquitoes start the day's work just 

 after sundown, and are very busy among the plants and 

 animal victims that furnish their food, till it falls dark, 



