HYMENOPTEEA. 151 



wood. The commoner species is Xyleborus dispar. They are 

 short broad beetles, shiny black in colour, with pitchy red elytra, 

 and covered with a yellowish pubescence : the females are from 

 ^ to 1^ of an inch long ; the males, which are rare, about JL. to 

 ■J^ of an inch. The beetles bore their way right into the wood 

 of young trees as well as old ones, and in these tunnels the white 

 larvae are got in May and June, feeding upon some fungoid 

 growth (Ambrosia) that lines the tunnels. The grubs pupate 

 in the same place, and we find the beetles in September placed 

 like a row of shot in the holes, and here they seem to remain 

 all the winter. X. Saxeseni can be told from X. dispar by the 

 thorax and elytra being more oblong in the male and narrower 

 in the female. The males of both have their wings atrophied. 

 Various other related forms of the genus Scolytus attack the bark 

 of forest and fruit trees, which we cannot enter into here. 



Prevention and Remedies. — ^All infested trees should be cut 

 down and burnt in such attacks, so as to stop the pests from 

 spreading. Remedies are useless practically, although several 

 are given in works on Economic Entomology. 



HYMENOPTERA. 



OR Ants, Bees, Wasps, Sawplibs, Gaij>plies, and Ichnbximons. 



The Hymenoptera include the Ants, Bees, Wasps, Sawflies, 

 Ichneumon Flies, Sirices, and GaU-fiies. Of these the Saw- 

 flies and the Sirices are very destructive ; Ants and Wasps are 

 sometimes noxious ; whilst the Ichneumon-flies form one of the 

 greatest groups of insect parasites, all the hundreds of species 

 living upon other members of the insect world. 



The Hymenoptera are insects with biting and sucking mouth- 

 parts, a completely fused prothorax, and four membranous 

 wings with few nervures and a dark stigma on the costa. 

 Metamorphosis is complete. The head is provided with two 

 large, compound, facetted eyes, and with three ocelli on the 



