INSECTS. 17 



minute scales, of various shapes and sizes on the 

 different species, and even on the different parts 

 pf the same animal. Their general appearance 

 is more or less fan-shaped, and they are disposed 

 in the manner of tiles on a roof, lapping over each 

 other. 



The fourth order is called Neitroptera, or nerve- 

 winged. The insects of this order are remarkable 

 for the reticulated appearance of the wings, the 

 fibres running into ramifications and decussations 

 over the whole surface. Thi-s order is exemplified 

 in the LibellulaB or Dragon-Flies, &c. in which 

 this character is remarkably conspicuous: the 

 wings are always four in number. 



The fifth order is called Hymenoptera, and con- 

 sists of insects furnished with four membranaceous 

 wings, and also with a sting, or a process resem- 

 bling one. It is exemplified in the weil-known in- 

 sects of the Bee and Wasp tribe and many others. 



The sixth o-rder is entitled Dipfera, and contains 

 such insect? as are furnished with two wino-s onlv. 



B 



In this order rank Flies, strictly so called, as well 

 as Gnats, and a great variety of other insects. 



The seventh and last order is termed Aptera, 

 and consists of such insects as are totally destitute 

 of wings, as Spiders, Centipedes or Scolopendrae, 

 Fleas, and many others. To this order also belong 

 the numerous species of the Crab and Lobster 

 tribe, which by some naturalists are excluded from 

 the class of Insects. It may be here observed, in 

 order to prevent mistakes, that some of the Cole- 

 opterous Insects are destitute of wings, having 



v. vi. P. i. 2 



