184 ELEMENTARY LESSONS ON INSECTS 



and caddisflies in their mating flights; when you find hosts 

 of nymphs emerging and transforming together, as do 

 cicadas, coming from the ground, or dragonflies, from the 

 pond ; when you find them accumulated after a storm at the 

 drift line on sandy lake beaches as often are many beetles; 

 or, when the picking is good, on flowers, at lights, etc. 



For purposes of study of skeletal parts, no material is 

 better than cast skins, and these can often be found abun- 

 dantly where transformations have occurred. Preserve these 

 dry in small boxes or vials and use them for slide mounts. 

 Exercise foresight, and provide against future needs. 



