CHAPTER VI 

 BEETLES 



BEETLES (which make up the thirteenth order 

 of insects viz., Coleoptera) may almost always 

 be recognized by their thickened fore- wings, or elytra. 

 These act as covers, beneath which the membranous 

 hind-wings are folded when they are not in use. The 

 mandibulate mouth-parts are not unlike those of the 

 order Orthoptera, but the second maxillae are very 

 intimately united. The dorsal plate of the first 

 thoracic segment (pronotum) is generally large, while 

 a scutellum is often visible between the bases of the 

 elytra. The legs vary greatly in shape, but the coxae 

 of the hind pair are almost always large and powerful. 



Beetles undergo a complete metamorphosis. Their 

 life-stories are very varied, and the larvae differ greatly 

 in appearance, ranging from active creatures with a 

 hardened cuticle, to soft, legless grubs. The wings 

 are developed inwardly, and do not become visible 

 until after the penultimate moult. The full-grown 

 larva often constructs a cocoon. The pupa is " free " 

 i.e., its appendages, though lying close to the body, 

 are not immovably fixed thereto by a general harden- 

 ing and thickening of the outer skin. 



This is probably the largest order of insects. 

 Upwards of 3,400 British species have been described. 

 The classification of this vast army is far from com- 



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