16 



GUIDE TO CALIFORNIA INSECTS 



The primary classification of insects into orders was originally based on 

 the wings, beginning with the homy winged beetles and ending with the 

 wingless forms. Next the method of taking food was made the basis of 

 separation into two great groups, the biting and the sucking insects. This 

 has of late been largely replaced by a division based on the development 

 those with primitive and simple metamorphosis in one series and those with 

 complex and hypermetamorphosis in the other. None of these plans seem 

 wholly satisfactory; that adopted in this book is chronological, that is the 

 orders are given in the sequence of their appearence on earth as shown by the 

 geological record. 



Figure 12. Wing attachment in Cicada. JL,etteis tlie same as i<Mgure 10. 



The table following gives the original Linnaean system and that given 

 in five recent textbooks. Folsom alone separates the CoUembola from the 

 Aptera and Comstock alone the Euplexoptera from the Orthoptera. Both 

 Comstock and Kellogg separate the Mallophaga and Isopoda from the Corro- 

 dentia, and Comstock and Folsom the Siphonaptera from the Diptera. The 

 author differs from the majority regarding Thysanoptera tho all agree as 

 to its location in the series. He differs from all five by placing the Neuroptera 

 and allied forms with the Plecoptera, agreeing rather with most of those who 

 have specially studied these groups in the belief that they are very closely 

 allied despite the difference in metamorphosis. If these groups were 

 made distinct orders, the historical arrangement would place Neuroptera just 

 below Coleoptera, the Mecoptera below Diptera and Trichoptera antedating 

 Hymenoptera and Lepidoptera. 



The placing of- Ephemerida lowest of the winged insects by Comstock 



