CLASSIFICATION OF INSECTS. 85 



Order Coleoptera (Co-le-op'te-ra). 

 The Beetles. 



The members of this order have a pair of horny wing- 

 covers, called elytra, which meet in a straight line down 

 the back, and beneath which there is a single pair of mem- 

 branous wings. The mouth-parts are formed for biting. 

 The metamorphosis is complete. 



Beetles can be readily distinguished from all other 

 insects except earwigs by the 

 possession of horny, veinless 

 wing-covers, which meet in a 

 straight line down the back 

 (Fig. 79); and they differ from 

 earwigs in lacking the pincer- 

 like appendages at the tail end 

 of the body characteristic of 

 those insects (see page 70). fig. 79.-A beetle. 



Beetles also differ from ear- 

 wigs in having a complete metamorphosis. 



The name of the order Coleoptera is from two 

 Greek words : coleos, a sheath, and pteron, a wing. 

 It refers to the sheathlike structure of the elytra 

 (el'y-tra) or wing-covers, which were formerly be- 

 lieved to be modified wings. 



This order has been studied in Lessons XVIII to 

 XX, and several families are described in the follow- 

 ing chapters. 



Order Hymenoptera (Hy-me-nop'te ra). 

 Bees, Wasps, Ants, and Others. 



The members of this order have four wings ; these 

 are membranous, and furnished ivith comparatively few or 



