202 Mosquitoes 



formalin. Alcohol makes them shrink and grow 

 brittle, the hairs fall off the larvae, and all sculpture 

 disappears from the eggs, which are thus absolutely 

 spoiled save for general shape and size. No sculpture 

 can be seen on mounted eggs. Formalin, with a few 

 drops of glycerine, will not injure the fingers and will 

 keep the specimens perfect, shapely, and pliable. 

 Dissections of larvae are best studied fresh, and will 

 not mount so very well, but formalin specimens can 

 be used. Mounted skins are of little use, as the hairs 

 show on both sides apparently ; it is almost impos- 

 sible to tell on which side the hairs are, as such skins 

 curl up and are shapeless. Skins of the different 

 stages should be carefully preserved in formalin, 

 each stage in a separate bottle, and examined in water 

 on a slide. For dissection of the mouth-parts, skins 

 are better than whole larvae, the parts being far less 

 apt to be broken. Do not put labels in the bottles; 

 they ruin the specimens by breaking the hairs, un- 

 less the label be fastened to the sides. The label 

 may be pinned on the cork with short insect pins. 



