THE CLASSIFICATION OF INSECTS 77 



Both families are found in all parts of the world, and 

 there are a number of British species. 



The Coniopterygidce are very small insects which 

 secrete a white, powdery substance that covers the body. 

 They are distinguished from other Neuroptera by their 

 short wings, which have very few transverse nervules, 

 and by the very small size of the hind pair. Some of 

 their larvae are known to feed upon scale insects. 



Ordek XIII. — Coleoptera. 



This, by far the largest order of insects, comprises the 

 beetles, most of which may at once be recognised by their 

 hardened fore-wings, or elytra, beneath which the hind- 

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

 wings are occasionally reduced or absent (in the latter 

 case the elytra may be fused together along their middle 

 edges, forming a kind of shield above the abdomen) ; 

 more commonly, however, they are well developed. The 

 dorsal plate (pronotum) of the first thoracic ring is very 

 large in all beetles ; while the corresponding plate of 

 the middle thoracic segment (mesonotum) is often visible as 

 a triangular piece, called the scutellum, between the bases 

 of the elytra. The legs vary greatly in accordance with the 

 insect's manner of life, but the coxae of the hind pair are 

 usually large and powerful. The mouth-parts are formed 

 for biting, and in some respects are reminiscent of the 

 order Orthoptera ; the second maxillae, however, are very 

 intimately fused together to form the lower lip or labium. 

 In their development, beetles pass through a complete 

 metamorphosis. The larvae are very variable in form, 

 and are active (campodeiform), or more or less sluggish 

 and grub-like (eruciform), according to their manner 

 of life. Generally speaking, the larvae of a given family 



