SC0LYT3 DJE. 



197 



arrangement (Gen. Col. vi & vii) he begins by adopting two 

 leading divisions or " legions " : — 

 T. Maxillae covered by the mentum except 

 occasionally at the base ; sub-mentum 



without peduncle CtntcuLiONiDiE Adelognathi. 



EI. Maxillse not covered by the mentum ; 

 sub-mentum as a rule plainly pedun- 

 culate CURCULIONIDJE PHANEROGNATHI 



These are again divided and subdivided into " cohorts,' 

 phalanxes," " sections," and " tribes " in bewildering succession. 

 Lacordaire, moreover (I. c. vii, p. 1, note), confesses that he cannot 

 hide from himself the weakness of one of his chief divisions, 

 which apparently bristles with exceptions, so that it is impossible 

 to accept it as final, and yet it must be allowed that no one 

 has, as yet, really superseded his arrangement. In the present- 

 state of own knowledge, then, it would seem that the genera! 

 question of the classification of the family must be left in abeyance. 

 The discovery of new forms is perpetually altering our ideas of the 

 Coleoptera, and in no group will new forms be more constantly 

 discovered than in the one under consideration. 



Family 97. SCOLYTIDtE (IPIDJE). 



Head variable in form, with the rostrum short and broad and, in 

 maw/ cases, practical}}/ absent ; mandibles stout, carved, more or less 

 denticulate on their inner side; prothorax variable, but usually large 

 and as broad as the elytra ; anterior coxae usually contiguous ; legs 

 compressed, anterior tibiae almost always denticulate or crenulate on 

 their outer side ; tarsi variable, last joint long. 



The members of this family are for the most part small and 

 cylindrical insects, which are eminently adapted by their shape 

 for their wood- and bark-boring habits ; in very rare cases, as in 

 the curious male of Xyleborus dispar, the form is more or less 

 globose. A very few of the species are known to feed in the 

 stems of plants or in dried fruits ; those belonging to the genus 

 Thamnurgus, Eich., for instance, live in the stems of Euphorbia, 

 Delphinium, and other plants. As a rule they burrow between 

 the wood and the bark, but some species bore into the solid 

 wood (Trypodendron, etc.), and the family as a whole is Aery 

 injurious. The insects have been defended on the ground that 

 they only attack decaying and doomed trees, but the truth appears 

 to be that sound trees are first penetrated by the perfect insects 

 and thus become weak and sickly, and the larva3 of these and 

 other species of wood-feeding beetles complete their destruction 

 (v. Brit. Col. v, p. 400). 



