Order 157 



structure a marked approach to the Caddis-flies which 

 form the order Trichoptera usually held to be distinct 

 from the Lepidoptera. 



Comparing now the Butterflies which we have just 

 been studying with the Cockroach wherewith we 

 began our enquiries into insect-structure, we notice 

 that it does not possess any one of the features 

 mentioned above as characteristic of the Lepidoptera. 

 It has strongly developed mandibles, and the first 

 maxilljE are primitive jaws not in the least modified 

 as a sucking-organ. The wings differ markedly in 

 shape from those of Butterflies or Moths, are totally 

 devoid of any scaly covering, and have their surface 

 covered by a close network of nervures. The young 

 Cockroach is hatched from the egg in a form closely 

 resembling its parent, except that it has no wings. 

 Differing thus, there can be no hesitation in referring 

 the Cockroach to an order of insects entirely distinct 

 from the Lepidoptera. It belongs to the order of 

 the Orthoptera or straight-winged insects. 



Commencing an enquiry into the classification of 

 insects with the difference between two varieties of 

 butterfly we have passed upwards through increasing 

 divergences of form to the distinction between some 

 of the Orders into which the whole Class of insects 

 is divided. In classifying any individual insect, it is 

 evident that the reverse order to this must be 

 followed ; the order must first be determined, then 

 the family, then the genus, and finally the species and 

 variety. 



The Search for a Natural Classification. — It 

 will have been evident to the reader of this chapter 

 that insect-classification is a more or less uncertain 

 thing. The limits which mark off' species, genera, 

 families, and even orders from each other depend 

 largely on the judgment and opinion of the naturalist. 



