CLASSIFICATION OF INSECTS. 



21 



insects which resemble worms has also an analogous form to 

 the M.yriopods ; so spiders are analogous to Crustacea, while 

 reminding us of the pupa state of the winged insects. 



Moreover, worms and Crustacea are, generally speaking, 

 aquatic, breathing by gills, while insects are terrestrial and 

 breathe by pores in the side of the body which communicate 

 with a complex system of air tubes, sometimes enclosed by 

 blood vessels. 



The order of winged insects is subdivided into seven divi- 

 sions, occupying an intermediate rank between orders and 

 families, and called by naturalists suborders.* Of these the 



Fig. 14. Fig. 15. Fig. 10. 



Mutilla. Aut (Formica). Chalcid Parasite. 



Hymenoptera seem to be highest in the scale, and the Neurop- 

 tera the lowest. 



Hymenoptera (Bees, "Wasps, etc. Fig. 14, Mutilla; Fig. 15, 

 Ant; Fig. 1G, a Chalcid parasite) are known by their hard, 

 compact bodies, distinct head and thorax, the small, narrow, 

 irregularly veined wings, and by the possession of a hard 

 ovipositor, often forming a poisonous sting. Their transfor- 

 mations are the most complete of all insects, the larva being 

 most generally a white, footless, helpless grub, partly curved, 

 and rapidly tapering at each end. The pupa has the limbs 

 free, contained in a thin, silken cocoon. The species are all 

 terrestrial. 



Lepidoptera (Butterflies and Moths. Fig. 1 7, Alypia, or grape 

 moth and caterpillar) have the mandibles obsolete, the max- 

 illae greatly prolonged and rolled up between the labial palpi ; 

 their bodies are covered with scales ; and the broad, regularly 



* Or, if preferred, tliese seven divisions may be regarded as orders, and the 

 three " orders " of insects as subclasses. 



