COLLECTION AND PRESERVATION OF INSECTS 35 



Figuee 28.~ Hemiptera. The oystershell scale (Lepidosaphes ulmi (L.) ), on lilac. 

 Actual length of the large scale insects about 2.5 mm. 



COLEOPTERA 



Coleoptera (beetles and weevils) are usually winged, with two pairs 

 of wings, the front pair thick and forming a hard shell and meeting 

 in a straight line down the middle of the back. The hind wings are 

 membranous and are folded under the front wings when at rest. The 

 mouth parts are formed for chewing. The immature stages are grub- 

 like or wormlike, and the insects pass through a pupal stage before 

 becoming adults. The food habits are varied; some feed on living 

 plants, some are predaceous, some are scavengers, and some bore in 

 wood. This order includes some of the best known and most important 

 of our insect enemies. ( See figs. 29, 30, 31, and 32.) Most of the mem- 

 bers are terrestrial but a few are aquatic. 



Figure 29. — Coleoptera. Striped blister beetle (Epicauta vittata (F.)). Actual 



length about 18 mm. 



