244 THE MOSQUITOES. 



have long lateral branching hairs, and on the sides of each of the 5 or 6 

 middle abdominal segments they have a pair of palmate hairs. These 

 palmate hairs are supposed to aid them in keeping their position on the 

 surface of the water. The larvae are usually called "wigglers." 

 The duration of the larval stage is from i to 2 weeks, according to the 

 temperature. 



THE PUP^:. 



These have a bloated-looking cephalo-thorax and a shrimp-like 

 tail the latter the abdomen. Very important in examining them with 

 a lens is to note the characteristics of the syphon tubes which project 

 from the dorsal surface. These syphons are long and slender in 

 Culex and project from the posterior portion of the head end. In 

 Anophelinae they are broadly funnel-shaped and arise from the 

 middle of the head end. The syphon of the Stegomyia is triangular. 



The bulbous end of the Culex nymph is more vertical than the 

 horizontally-placed cephalo-thorax of Anopheles. The duration of 

 pupal life is short only 1-3 days. At the end of this time the pupa 

 comes to the surface and straightens out. The integument then 

 splits dorsally and the perfect insect emerges. It dries its wings for a 

 time on its raft-like pupal skin and then flies away. 



From the above it will be seen that the stages in the metamorphosis 

 of the mosquito takes about 2 weeks: 1-3 days for egg stage; 7-10 days 

 for larval stage and 2-3 days for pupal stage. 



DISSECTION OF THE MOSQUITO. 



The easiest way to secure a mosquito for dissection is to use an 

 ordinary plugged test-tube. Slipping the open end of the test-tube over 

 the resting mosquito; by a slight movement, the insect will fly toward 

 the bottom. Then quickly insert the plug. If it is not desired to 

 study the scales, the best way to kill the mosquito is by striking the tube 

 sharply against the thigh. If it is also desired to study the scale 

 characteristics it is better to put a drop or so of chloroform on the lower 

 part of the cotton plug. The vapor falls to the bottom of the tube and 

 kills the mosquito. Take the mosquito out, pull off legs and wings and 



