THE HEAD. 23 



but, even in the young state, it is usually harder, 

 smoother, and of a different colour from the body. 



In animals which have a bony skull the head is 

 always more or less round ; this being both the most 

 capacious form, and the most difficult to injure by 

 accidents, circumstances so important in protecting 

 the brain ; but in insects which have no brain, the 

 head, though in most cases round, is often of various 

 shapes ; as somewhat square and angular in the 

 stag-beetle, flat and wedge-like in wasps and bees, 

 and nearly triangular in some of the bugs. In the 

 weevil and scorpion fly, again, it is long and pointed, 

 while in some beetles and- four-winged flies it tapers 

 backwards into a long neck ( J ). 



Minute naturalists are not yet agreed about the 

 divisions of the head, and M. Audouin first says, " it 

 can be demonstrated that it is composed of several 

 segments ; " and again he .says, " it is composed of 

 rather solid walls, most frequently presenting no trace 

 of junction, so that it appears at first view quite 

 simple, though an experienced eye soon discovers it 

 to be the result of several segments the number not 

 yet determined, united together." That is, as it 

 appea,rs to me, a theorist, accustomed to find that the 

 bones of a skull can be separated, readily imagines 

 junctions of pieces in the head of an insect, though he 

 acknowledges them to be imperceptible. 



The head of insects, like that of other animals, con- 

 sists of the crown and forehead, (both of which M. 

 Meckel objectionably calls the skull), and the face; 

 but the extent of the cheeks is seldom very distinct. 

 It is not so with the mask( 2 ), as we may call it, a part 

 which on the one side is jointed with the front or face, 

 and on the other with the upper lip, which it covers; 



(1) In Latin, Collum. 

 (2) The mask is termed by the French, Chaperon ; in Greek, 



