CLASSIFICATION OF INSECTS. 329 



constant destruction to which, from their small size, insects 

 are so pre-eminently liable, and against which their instinct, 

 in all states of their existence, is brought into full play, is 

 nevertheless necessary to preserve a just proportion between 

 all the tribes of the creation. Hence we may firmly believe 



" All discord" to be " harmony not understood ; 

 All partial evil, universal good." 



SECTION V. 

 CLASSIFICATION OF INSECTS. 



Having already given, in the introductory part of this 

 volume, a sketch of the rise and progress of Entomological 

 science, which necessarily included a concise notice of the 

 various plans suggested for the classification of insects, I 

 shall here confine myself to a sketch of the Linnaean system, 

 as having been very generally adopted, until lately, in this 

 country, and to the more material changes which have been 

 subsequently introduced. 



Linnaeus adopted the structm-e of the wings as afibrchng 

 the characters of his orders, which were as follows : — 



1 CoLEOPTERA. — ^Wiugs, four ; the upper pair crusta- 

 ceous, with a straight sutm-e. (Beetles and earwigs.) 



2. Hemiptera. — Wings, four ; the upper pair semi- 

 crustaceous and incumbent. (Locusts, bugs, tree-hoppers, 

 plant-lice, &c.) 



3. Lepidoptera. — Wings, four, imbricated with scales. 

 (Butterflies, moths, &c.) 



4. Neuroptera. — Wings, four, membranaceous; anus 

 unarmed. (Dragon-flies, &c.) 



5. Hymenoptera. — Wings, four, membranaceous ; anus 

 armed mth a sting. (Bees, wasps, ants, saw-flies, &c.) 



6. Diptera. — Wings, two ; halteres, two, in the place of 

 the posterior wings. (Fhes.) 



F F 3 



