18 INSECTS INJURIOUS TO VEGETATION. 



the legs free. These insects, of which there are many different 

 kinds, are intermediate in their characteristics between the He- 

 miptera and the Diptera, and seem to connect more closely these 

 two orders together. 



The ear-wigs (Forficulado'.)^ of which also there are many 

 kinds, were placed by Linnaeus in the order Coleoptera, but most 

 naturalists now include them among the Orthoptera ; indeed they 

 seem to be related to both orders, but most closely to the Orthop- 

 tera, with which they agree in their partial transformations, and 

 active pupae. They form the little order Dermaptera of 

 Leach, or Euplexoptera of Westwood. 



The spider-flies, bird-flies, sheep-tick, &c. {Hippoboscncla), 

 which, with Latreille and others, I have retained among the 

 Diptera, form the order Homaloptera of Leach, and the 

 English entomologists. 



The May-flies, or case-flies [Phryaneacl(E)^ have been separat- 

 ed from the Neuroptera ; and constitute the order Trichop- 

 tera of Kirby. Latreille and most of the naturalists of the 

 continent of Europe still retain them in Neuroptera, to which 

 they seem properly to belong. 



The order Bomboptera of MacLeay, was made to in- 

 clude the horned-tailed wood-wasps (Uroceridce) ^ which, how- 

 ever, are retained in the order Hymenoptera by all other natural- 

 ists. In form and habits the larvae of these insects closely resem- 

 ble the wood-eating larvae of some beetles. Certain intermediate 

 groups connect them, however, with the saw-flies {Tcnthredin- 

 ida), and the latter, though truly Hymenopterous insects, ap- 

 proach the Lepidoptera in the forms and habits of their larvae, or 

 false caterpillars, and in the nature of their transformations. 



The Thrips tribe consists of minute insects more closely allied 

 to Hemiptera than to any other order, but resembling, in some 

 respects, the Orthoptera also. It forms the little order Thy- 

 sanoptera of Haliday ; but I propose to leave it, as Latreille 

 has done, among the Hemiptera. 



The English entomologists separate from Hemiptera the cica- 

 das or harvest-flies, lantern-flies, frog-hoppers, plant-lice, bark- 

 lice, &c., under the name of Hojioptera; but these insects 



