510 



FLY MAGGOTS AND MYIASIS 



the characters used in distinguishing genera and species of fly 

 maggots. A few typical forms are shown in Fig. 243. 



It is more convenient to consider the different types of myiasis 

 according to the way in which the larvae attack the body or ac- 

 cording to parts affected than according to the families and genera 

 to which the flies belong. We may divide the various flies 



Cochllomyia r>acel!aria(X50> 



Oestrus ov/s w^o? 



FIG. 243. Posterior stigmata and breathing pores of various maggots. Note 

 distance apart of opposite stigmal plates, form and position of spiracles, pres- 

 ence or absence of button, etc. 



causing myiasis into four groups: (a) those in which the larvae live 

 outside the body and suck blood by puncturing the skin, (6) 

 those in which the larvae develop under the skin; (c) those in 

 which the eggs or young larvae are deposited in wounds or in 

 natural cavities of the body, such as the nose, ears and vagina; 

 and (d) those which live in or pass through the intestine or uri- 

 nary passages. 



