126 



INSECTA OE HEXAPODA. 



unlike the adult, and where there is a distinct quiescent pupa, 

 in which the larva is transformed into the imago, are said to 

 undergo a complete vietamoi-phosis. There are many insects 

 which have no quiescent pupal state, and where the larva is 

 very similar to the adult. The whole life-cycle from the egg 

 onwards is one of activity except when the insect is moulting. 

 The pupal stage is simply distinguished by the small swollen 

 wing-buds seen at the sides of the thorax. These insects are 

 said to have an incomplete metamorphosis. 



Insects are classified partly by the structure of the mouth, 

 partly by the structure of the wings, and also by their metamor- 



S 



a'lG. 54, — Alimentary Canal of Larva {Ti%yula paludosa). 

 a, Mouth; h, gullet; c, proventriculus ; c, Ofeca ; d, stomach; /, hepatic tul)es; 

 (/, small intestine ; i ami h, large intestine ; j, rectum ; k, anus ; ;, anal gland. 



phosis. Those with biting mouths are called 2Iani]ilndata ; 

 those with sucking and piercing mouths, Hmistellata. Mandib- 

 ulata include the Beetles, Grasshoppers, Cockroaches, Ants, 

 Bees, and Wasps. The Butterflies and Moths, Flies, Bugs, and 

 Plant Lice are Haustellata. This arrangement is not at all 

 satisfactory, as we get insects in eacli with a complete and 

 incomplete metamorphosis. All insects may now be grouped in 

 nine orders, as follows : — 



1. Goleoptet-a, or Beetles. 



2. Ilijmenoptera, or Ants, Bees, ^Vasps, Sawflies, &c. 



