DISSECTION OF THE MOSQUITO 



3 11 



are long and slender in Culex and project from the posterior portion of the head 

 end. In Anophelina? they are broadly funnel-shaped and arise from the middle 

 of the head end. The siphon 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 

 one to three 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 mos- 

 quito take about two weeks: one to three days for egg stage; seven to ten days for 

 larval stage, and two to three days for pupal stage. 



DISSECTION or 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, 



FIG. 93. Anatomy of mosquito, i, Cross section of proboscis of mosquito; 2, 

 anatomy of mosquito, longitudinal section; 3, tip of proboscis of mosquito; a, labrum- 

 epipharynx; b, hypopharynx; c, manidible; d, maxilla. 



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 then place the 

 body in a drop of salt solution on a slide. Bile has been recommended. Then 

 hold the anterior end of the thorax by pressure of a needle. With a needle 



