142 



forwards into the ill-defined haemocoele spaces amidsf 

 the organs. The main function of the circulation is the 

 distribution of soluble food and the removal of wastes 

 and fat ; the respiratory function is discharged chiefly 

 by the tracheae. 



THE ORDERS OF INSECTS. 



BlOOd-SUCking insects, and Orders to which blood-sucking species belong, 



are marked *. 

 The insect parasites of Man belong to the Orders marked f . 



Order APTERA. Wingless. STo metamorphosis. 

 Order ORTHOPTERA. Metamorphosis incomplete. 



Examples, Earwig, Cockroach (Periplaneta, Blatta), 

 Leaf-insect, Stick-insect, Locust, Cricket. 

 Order NEUROPTERA. Metamorphosis variable. 



Examples, Termites. Social, living in communities* 



and showing polymorphism. 



Order MALLOPHAGA (Biting Lice). Wingless. Metamorphosis slight. 

 Example, Trichodectes. A biting louse of dogs and 



other quadrupeds. 



Order HYMENOPTERA. Metamorphosis complete. Many are social, 

 living in communities and showing polymorphism. 



Examples, Bees, Wasps, Ants. 



Order COLEOPTERA (Beetles). Metamorphosis complete. 

 Order LEPIDOPTERA. Mouth-parts of perfect insect or imago for 

 sucking only. Metamorphosis complete. 



Examples, Butterflies and Moths. The social " pro- 

 cessionary caterpillars " of the moth, 

 Cnethocampa, cause " urticaria epi- 

 demica " in certain parts of Europe. 



*tOrder DIPTERA (Two-winged Flies). One pair of wings, the hind 

 pair having been reduced to knob-like balancers (halteres). Mouth- 

 parts for piercing and sucking, or for sucking only. Metamorphosis 

 complete. The larvae are footless maggots, often without a head, 

 but with a mouth. The pupa in many instances is within a pup- 

 arium (the moulted skin of the larva). Many are important (blood- 

 sucking species, germ carriers, parasitic larvae) in relation to disease. 

 *Family Simulidae. *Simulium. The females of various species 



attack domestic animals and Man. 



Family Cbironomidae (Midges). * Ceratopogon or Culicoides. 

 Family Psychodidae (Owl-midges). *Phlebotomus papatasi. 

 Attacks Man and transmits germ of papatasi or phlebotomus 

 fever in Southern Europe (Malta), Africa and India. 



