BEETLES. 3 



nothing, or have disappeared entirely. In many cases of this kind 

 we find that the wing-covers do not simply meet on the back, but 

 that they are actually soldered together, so that the elytra form one 

 solid piece; the suture can, however, readily be detected. (Com- 

 pare illustrations 180 and 181). 



The exposed parts of the body of most beetles are very hard 

 and horny. This is at least the case with all such as lead an 

 active life, and is very necessary to their very existence, not only 

 as a protection, but also because the muscles enabling them to run 

 or fly have to be fastened to this exterior skeleton. Less active 



Fig. 3. — Upper surface of Cicindela: eos2, episternum of meso-thorax; epm 

 epimeron of meso-thorax; scutel/.. scute'lum; scuts, scutumof meta-tkorax; £> — 

 DS, dorsal segments of abdomen; J, vena tnarginalis; //, vena mediastina; III, 

 vena scapuHris; V, vena externo-media; VII, vena cubitalis, IX, vena interno- 

 media; XI, vena analis. After Ganglbauer. 



beetles, and all others in their earlier stages, in case they are not 

 forced to search for their food or when surrounded by some pro- 

 tecting material, as soil, wood, or fruits, are usually softer; their 

 outer covering, which is composed of chitine, a horn-like sub- 

 stance, is in such cases soft, frequently very much so. Such a 

 pliable skin is very important in the early stage of a beetle, as it 

 enables the larva to stretch during its rapid growth, and to form 

 the organs of the adult insect while changing to a pupa. 



The biting mouth-parts are well developed in all true beetles, 

 and we do not find some of them enlarged at the expense of 

 others, as in the case of butterflies and moths. The upper lip or 



