PHYSIOLOGY OF INSECTS. 107 



surface or throat (gula), and the lateral surface or 

 eyes {ocult). 



360. The epicranium is frequently divided by 

 a sutural line, passing across the forehead from 

 eye to eye. "When this is the case, the portion 

 so separated, and which immediately covers the 

 mouth, is called the shield (clypeus) : the gula 

 is often separated by a similar sutural line ; in 

 this case, the anterior portion adjoining the mouth 

 is called the chin {mentum). 



361. There are one, two, or three minute, trans- 

 parent, highly convex lenses, situated on the 

 crown of the head, into which they are closely 

 soldered ; these are called simple eyes (ocelli) : 

 all insects, except beetles, seem to possess them 

 more or less perfectly. 



362. The cranial feelers (antenna;) arise from 

 the skull in front of the ocelli, between the eyes, 

 and above the clypeus ; they are freely articu- 

 lated with the skull, and moveable in every 

 direction : they are composed of numerous 

 joints. 



363. In length, stoutness, shape, and clothing, 

 the antennee of insects are very various ; their 

 variations are the subject of nomenclature ; and, 

 moreover, aiFord excellent characters for descrip- 

 tions. 



364. Setaceous antennae (antennee attenuantes) 

 are those which are long, throughout slender, 

 and yet taper gradually to the apex ; the union 



