PHYSIOLOGY OF INSECTS. 107 



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

 eyes (oculi). 



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 (antennce) 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 antennae of insects are very various ; their 

 variations are the subject of nomenclature ; and, 

 moreover, afford excellent characters for descrip- 

 tions. 



364. Setaceous antennae (antennte attenuantes) 

 are those which are long, throughout slender, 

 and yet taper gradually to the apex ; the union 



