INSECTS 



plants, which they extract by puncturing the plant tissues; 

 they will also feed on the exuding juices of fruit, or on any 

 soft vegetable matter. The females, however, are notori- 

 ous for their propensity for animal blood, and they by no 

 means limit their quest for this article of food to human 

 beings. The male mosquitoes, apparently, very rarely 

 depart from a vegetarian diet. The pain from the bite of 

 a female mosquito and the subsequent irritation and 

 swelling probably result from the injection of the secre- 

 tion from the salivary glands of the insect into the wound. 

 It is said that the saliva of the mosquito prevents coagula- 

 tion ot the blood. 



Because ot the short time necessary for the completion 

 of the life cycle from egg to adult during summer, there 

 are many generations ot mosquitoes trom spring to tall. 

 The winter is passed both in the adult and in the larval 

 stage. Fertile females may survive cold weather in pro- 

 tected places; and larvae found in large numbers, frozen 

 solid in the ice of ponds, have become active on being 

 thawed out, and capable of development when given a 

 sufficient degree of warmth. 



The yellow-fever mosquito, now known as Aedes aegypti 

 but at the time of the discovery of its relation to yellow 

 fever generally called Stegomvia fasciata, is similar in its 

 habits during the larval and pupal stages to the Culex 

 mosquitoes. It lays its eggs singly, however, and they 

 float unattached on the surface of the water. The adult 

 mosquito may be identified by its decorative markings. 

 On the back of the thorax is a lyrelike design in white on a 

 black ground; the joints of the legs are ringed with white; 

 the black abdomen is conspicuously cross-banded with 

 white on the basal half ot each segment. The male has 

 large plumose antennae and long maxillary palpi. The 

 female has a strong beak, but small palpi, and her an- 

 tennae are of the short-haired form usual with female 

 mosquitoes. The species of Aedes shown in Figure 177 

 much resembles the yellow-fever mosquito, but it is a 



[ 33* \ 



