PARASITOLOGY. 21 



A?iimals .It tacked. — They produce irritation by their 

 numbers upon the skin or wounds of any animal, and 

 by imbibing the exudate and perspiration. They 

 carry germs from the wounds or excreta of one ani- 

 mal to another. 



MuscA VoMiTORiA(Vomitoria — causes vomiting, musca — fly.) 



Sy?t07iyi)is. — Blow-fly; bluebottle fly; calliphora 

 vomitoria. 



History. — Found widely distributed. 



Description. — The fly is about four times the size 

 of a house-fly. Its eyes are brownish in color ; thorax 

 and abdomen bluish green. 



Life Cycle.— The eggs are oval in shape and white 

 in color. They are deposited on decomposing ani- 

 mal and vegetable matter, in the wounds of animals 

 and in fresh manure and garbage. When the weather 

 is hot the eggs hatch in a very few hours. The 

 larvae are called maggots, and develop rapidly. 

 On reaching maturity the maggots, if in a wound, 

 drop to the ground and pass through the pupal stage 

 in a short time. 



LuciLiA Macellaria. 



Sy7io7iyi7is. — Screw-worm fly ; compsomyia macel- 

 laria ; cayor fly. 



Histo7y. — Found throughout the world. Its great- 

 est damage is done in hot 

 climates. 



Desc7nptio7i. — The fly is 

 about one-half inch in length 

 Fig. 1-Cayor Fly Larva. and of a bluish green color. 



a. Ventral View ; b, Side View. j^ j^^g ^^^j.^^ longitudinal 



black stripes on the dorsal surface of the thorax. 



