THE MOSQUITO 57 



Europe there may be three or four generations 

 in the course of the season : the first beginning 

 in April and the fourth taking place between 

 the middle of September and the middle of 

 October. After that date no larvae were 

 found. About four generations also occurred 

 in the neighbourhood of Cambridge, according 

 to observations of Professor Nuttall. 



Kerschbaumer has calculated that if the 

 average number of eggs laid by a female be 150, 

 the number of the descendants by the fourth 

 generation would amount to 31 millions. This 

 readily accounts for the fact that in certain 

 parts of the world they occur in perfectly 

 enormous numbers, and if it be true that 

 blood is essential for fertilisation and ovi- 

 position, very few of these potential mothers 

 can breed. In nature they will feed on a 

 great number of vegetable juices — melons, 

 wild cherry-blossom, bananas, oranges, over- 

 ripe mangoes ; they suck the ' juices ' of 

 allied species of insects just when the imago 

 is issuing from the pupa-case and before their 

 integument is hardened, or they pierce the 

 soft skin of the cicada, and occasionally 

 attack the chrysalids of a butterfly. One 

 of the most curious sources of food are very 

 young trout. The adult insect attacks these 

 yetits poissons filiformes, ' literally sucking out 

 their unsuspective little brains before they 



