114 



Wash in water, and stain lightly with methy- 

 lene blue. Wash in water, and allow to dry. 

 Warm gently to ensure complete dryness, and 

 place the coverglass, mid- gut downwards, upon a 

 drop of balsam upon a slide. 



The muscular fibres and other structures of 

 the mid-gut will be well exhibited. The zygotes 

 will be stained rather a dark blue. If not too 

 darkly stained, the pigment of the zygotes will 

 have the appearance it had in the fresh specimen. 



3. Mount directly in glycerine. 



4. For more minute histological examina- 

 tion, imbed the stomachs in paraffin or the 

 whole mosquito (vide p. 123). 



To Dissect Out the Salivary Glands 



This is quite a simple proceeding if it be re- 

 membered where they lie. They are intra-thoracic 

 structures, and they commence at the hinder por- 

 tion of the neck and end opposite the first pair of 

 legs. They lie ventrally, in fact, roughly speaking, 

 they lie just above the origin of the first pair of 

 legs (Fig. 34). 



The simplest and most rapid method, and the 

 one that hardly ever fails, is the following : — 



1. Place the mosquito in a drop of salt solu- 

 tion on its right side, with the head pointing to- 

 wards you, as you dissect. 



2. Place the needle of the left hand on the 

 thorax to steady it, and place the needle of the 

 right hand on the back of the head and make 

 steady gentle traction. 



3. If done carefully, it will be seen that the 

 head has pulled out a little mass of white tissue 



