239 



Examination of the Larva 



1. Some features,e.^.,feeding,are conveniently 

 studied by placing the larvae in a drop of water 

 in a watch glass. 



2. For examining under a high power, the 

 activity of the larva must be restrained by a cover; 

 glass. 



3. Permanent preparations ' may be made at 

 once by placing in strong formalin, then alcohol, 

 then oil of cloves, then balsam {vide p. 250). 



4. Beautiful preparations of the palmate 

 hairs, etc., are got by mounting the larval skeleton 

 thrown off at the time of pupation. 



Pupation 



Just before this process the larva becomes 

 quieter. The attitude also frequently alters, 

 becoming a hanging one, somewhat like that of 

 a Culex larva. 



In this condition larvae are very readily 

 killed by agitating the water (and it is difficult 

 to carry larvae in this stage without killing them). 



The change into the nymph is very sudden. 

 A few rapid motions and the larval skin is cast 

 off, leaving the characteristic nymph. 



The Nympha 



This stage in the. tropics usually lasts about 

 forty-eight hours. When first the larval coat is 

 cast the nymph is light in colour, and may be 

 readily overlooked. Later, the nymph becomes 

 darker, and towards the end and immediately 

 prior to the emergence of the imago, silvery patches 



