THE CLASSIFICATION OF INSECTS 83 



Mcloc. Reference has already been made to the remark- 

 able hypermetamorphosis which these insects undergo and 

 to their parasitic life in the nests of bees. To this family 

 also belongs the European blister beetle or " Spanish fly ' 

 (Lytta vesicatoria). 



Four other families constitute the group, or sub-order, 

 Rhynchophora. These insects, known popularly as weevils, 

 are distinguished from all other beetles by their four- 

 jointed tarsi and by the elongation of the head to form a 

 snout or rostrum. The Anthribidce and Brenthidce are 

 mostly confined to the tropics, but the Curculionidce are 

 numerous in all parts of the world. The rostrum is always 

 distinct, sometimes very long — as in the case of the nut- 

 weevil (Balaninus nucum). The larva? are always white, 

 fleshy grubs, usually without legs. Roth they and the 

 adult beetles are vegetable feeders. They attack all kinds 

 of plants in a great variety of ways, and are often very 

 injurious. The apple blossom weevil (Anthonomus porno- 

 rum), which destroys the flower buds of apple trees, occurs 

 wherever the apple is grown. Other species, such as the 

 corn and rice weevils (Calandra), feed upon stored grain. 

 The bark-beetles (Scolytidce) differ from the other 

 weevils in the slight development of their snout and in 

 their more cylindrical form. The females make tunnels 

 between the bark and wood of trees and lay their eggs 

 therein ; while the larva? feed upon the soft layer immedi- 

 ately beneath the bark. When full-fed they pupate at 

 the end of their burrows. Some species, such as the pine 

 bark-beetle (Hylurgus piniperda), do damage in the adult 

 state to the shoots of trees. 



The family Stylopidce includes a few small insects 

 which are generally regarded as aberrant beetles. The 

 adult males have broad hind- wings which fold lengthwise, 



