1889.] 



THE YOUNG NATURALIST. 



91 



importance, but when one pair are much larger than the other, or 

 present to the exclusion of the second pair, then the ailiferous seg- 

 ment is the larger of the two. 



Primarily, we may divide the Class Insecta into two large divisons, 

 placing under the one head all those furnished with four wings, and 

 under the other those possessing two wings only. The first section 

 alone includes eleven out of the thirteen known orders, in which the 

 character of the wings will be found to vary very greatly. Having, 

 then, as a basis, the classification adopted by Professor Westwood, 

 the Orders may be tabulated as follows, according to the character 

 and importance of the organs of flight, and in this rotation they will 

 be considered in the ensuing pages. 



II. 



With four mem- 

 branous wings, all 

 used for flight. 



With four wings all 

 used for flight. An- 

 terior pair greatly 

 reticulated, the pos- 

 terior membranous. 



With two membran- 

 ous posterior wings. 



III. The anterior tough 

 and coriacious at base, 

 the apex membranous 



With two mem- 

 branous wings. The 



IV. anterior horny or 

 leathery, and unfit 



for flight. 



V. With four nearly ob- 



solete wings. 



VI. With two membran- 

 ous anterior wings. 



VII. With two membran- 

 ous posterior wings. 



ORDER. 



Neuroptera 



Hymenoptera 



homoptera 



Lepidoptera 



Trichoptera 



Thysanoptera 



DERIVATION. 



Neuron, a nerve 

 Humen,3. membrane 

 Homios, alike 

 Lepis, a scale 

 Thrix, a hair 

 Thnsanos, a fringe 



Orthoptera Orthos, straight 



Heteroptera 



Coleoptera 



euplexoptera 

 Aphaniptera 



DlPTERA 



Strepsiptera 



Heteros, unlike 



Koleos, a sheath Beetles 



TYPICAL 

 EXAMPLES. 



Dragon Flies 



Bees and Wasps 



Cicades, Aphides 



Butterflies and 



Moths 

 Caddice Flies 



Thrips 

 Cockroaches 



Bugs 



Euplektos, well 



twisted 



Aphanes, obscure 



Dis, twice 



Streptos, twisted 



Earwigs 



Fleas 



Flies 



Stylopa 



