38 



FOREST ENTOMOLOGY. 



resented by most of the respective families. Tims the ground under- 

 neath yields the various orders of " ground - beetles " or Adeplier/a, 

 while in the air above many species may be caught from time to time 

 on the wing. Carrion-beetles may be found on " keepers' trees " and 

 in dead carcases, while the bark of trees affords hiding-places for 

 many species. 



It is, however, from the economic point of view that the Coleoptera 



are really of special interest to the forester, inasmuch as the various 



parts of the tree become the feeding-ground of respective families and 



species of beetles. Thus the roots are attacked by the larvge of certain 



species, the bark tunnelled and trunk 



bored by others, while some beetles are 



injurious to the foliage and shoots in 



both larval and perfect forms. 



In order to understand the anatomy 

 of beetles,^ it would perhaps be best to 

 take a common ground - beetle, trisect 

 it into its main divisions, • — viz., head, 

 thorax, and abdomen, — and then carefully 

 note the general structure of each division 

 and its respective appendages. This is 

 also very important from a biological 

 point of view, for undoubtedly if insect 

 anatomy be generally considered, it will 

 be found that there is not a difference 

 in structure of the various orders, but 

 simply a modification of similar parts. 

 The anatomy of the mouth parts of the beetle affords a very good 

 case in point. 



Head. — Viewed from the top side, the eyes and antennre are the 

 most salient features. Fig. 39 shows all the respective parts : I is the 

 labrum or u]iper lip, which can be seen from the upper side. Ac- 

 cording to writers on beetle anatomy, the portion immediately behind 

 this, h, is called the clypeus, c, or shield of the mouth, and behind 

 this is the head proper, b. 



In the Ehynchophora the head is prolonged into a snout, called 

 the rostrum, which is a true portion of the head, and in no sense a 



1 For full particulars of structure, the student is adviser! to consult Fowler's 

 ' Coleoptera of the British Islands,' vol. i. 



-IlcadofCic 

 (marinifird). 

 «, '.vith jaws clnsetl ; h, witli jaws 

 open ; /,, labrum ; c, clypeus. 

 (From Fowler's ' British Coleop- 

 tera.') 



