24 INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



INSECTA OR HEXAPODA (Class) 



INSECTS 

 ORDERS 



The following study is based on the order as a unit of arrangement 

 instead of the food plant, as is so often the case of works on economic 

 entomology. This is done with the desire of avoiding the constant 

 mixing of insects belonging to different orders, families and genera, 

 to prevent repetitions, to give a more comprehensive idea of the rela- 

 tionships of insects and the corresponding relations of control 

 measures. 



The orders are arranged in chronological sequence, beginning with 

 those first appearing in the oldest fossils. The arrangement is the one 

 used by Prof. C. W. Woodworth, except that the Thysanoptera are 

 placed in a separate order and not along with the Hemiptera. 



1. Aptera.— Silver-fishes, silver-moths, spring-tails, bristle-tails, etc. 



(tSymphleona, *Thysanura, fMachiloidea, fDicellura, tRhab- 

 dura, tProtura.) 



2. Neuroptera.— Lacewings, ant-lions, caddis-flies, scorpion-flies, etc. 



(tRhapidoidea, jMegaloptera, *Mecoptera, *Trichoptera, 

 *Plecoptera.) 



3. Odonata.— Dragon-flies. 



4. Ephemerida.— May-flies. 



5. Corrodentia. 17 — White-ants, psocids, book-lice, bird-lice, etc. 



(*Isoptera, fEmbioptera, Mallophaga.) 



6. Orthoptera. — Cockroaches, earwigs, walking-sticks, mantids, 



crickets, katydids, grasshoppers. 



(fZoraptera, tMantoidea, tPhasmoidea, tBlattoidea, fDiplo- 

 glossata, *Euplexoptera.) 



7. Thysanoptera.— Thrips. 



8. Hemiptera. — Cicadas, lantern-flies, spittle insects, leaf -hoppers, 



tree-hoppers, jumping plant lice, plant lice, scale insects, 

 white flies and bugs. 



9. Coleoptera.— Beetles. 



(tAcreioptera, fStrepsiptera.) 



10. Diptera.— Flies and fleas. 



( tHomaloptera, *Siphonaptera.) 



11. Hymenoptera. — Horntails, sawflies, wasps, bees, ants, etc. 



12. Lepidoptera.— Moths and butterflies. 



tGroups or orders not largely accepted. 

 ♦Additional orders frecjuently used by other authors. 



^Mallophaga and Corrodentia are considered separate orders by Comstock and 

 Kellogg and as suborders of Platuptera by Folsom. 



