24 SCHOOL ENTOMOLOGY 



and in many cases the orders will not even be divided 

 into the families, 



The number of orders of insects recognized by the 

 various authorities ranges from seven, in the earlier class- 

 ifications, to over twenty, in the latest works. We recog- 

 nize here twenty, that number being chosen because it 

 seems to suit the needs of the present occasion better than 

 the greater number of the most modern authorities, even 

 though the latter schemes are doubtless much more nearly 

 scientifically correct. The names employed are those in 

 most general use. The table appended will enable the 

 student to identify to the order any of the common insects. 



Of the twenty orders here mentioned, six may be con- 

 sidered as major orders, the others being less important 

 because of fewer species and less economic importance. 

 The major groups are the Orthoptera, the Hemiptera, the 

 Lepidoptera, the Coleoptera, the Diptera and the Hymen- 

 optera. Any attempt to rank these according to their 

 degree of importance would be futile, although the Cole- 

 optera includes the greatest number of species. 



The complete list of orders is as follows: 



Thysanura Orthoptera 



Ephemerida Hemiptera 



Odonata Neuroptera 



Plecoptera Mecoptera 



Isoptera Trichoptera 



Corrodentia Siphonaptera 



Mallophaga Lepidoptera 



Euplexoptera Coleoptera 



Siphunculata Diptera 



Physopoda Hymenoptera 



