STRUCTURE. 



9 



namely, the head, thorax and abdomen, as shown in the diagram 

 of a Cockroach in the cover of Case 1. The head bears a pair of 



Fig. 5. 



Beetle (Blephily diet jejunum), dissected. (1016.) 

 a, head; b, prothorax; c, mesothorax ; d, metathorax ; e, abdomen. 



organs called antennae, and has two " compound " eyes. It is 

 sometimes imbedded in the thorax as in grasshoppers, beetles, etc. ; 

 in other cases it is free, being only attached to the thorax by a 

 membranous neck, as in flies, wasps, etc. 



