48 THE SIX-FOOTED INSECTS 



stages are said to \\a.\e incomplete metamorphosis (hetero- 

 metabolic). Those which have very striking or marked 

 differences between these stages, inchiding the distinctly 

 quiescent, non-feeding pupa stage, are said to have complete 

 metamorphosis (holometabolic). A third group is sometimes 

 noted for the primitive forms in which no change whatever 

 occurs, and in which no wings have developed, they being 

 said to be without metamorphosis (ametabolic). 



A reference to some of the common injurious species, 

 in which the different stages are shown, will illustrate these 

 different phases of develo])ment. 



CLASSIFICATION OF INSECTS. 



At this point it is well to discuss in a brief way what is 

 termed the classification of insects. When we speak of 

 the different members of the animal kingdom or describe 

 some particular insect it is quite important that we have 

 and use a name which would be distinctive for that one 

 form. The general practice is to use two names for each 

 insect, namely, the genus name and the species name. 

 A species includes those which are similar in habits and 

 characteristics and that may interbreed as a species or a 

 kind. A genus includes a number of species and a group of 

 genera with more general similarities form a family, and 

 families are grouped into orders. The order then is the 

 more general group and the class insecta includes about 

 twenty orders. 



Apterygota (Primitive Wingless Insects). 



Order 1. Thi/saitura, Bristle tails; Campodea, Lepisma. 

 Order 2. (\)UcinhoJa, Spring tails; Podura, Smynthurus. 



Pterygota (Winged Insects). 

 With Inconiphie Metamorphosis. 



Order 3. Orthoptera; Cockroach, locust, cricket, mole 

 cricket, "walking stick," "walking leaf." Biting mouth 



