MYIASIS. 



237 



mistaken for flukes. They also have a tendency to be attracted by 

 those with ozena and the larvae may develop in the nostrils. 



Chrysomyiamacellaria. This is known as the screw-worm when 

 in the larval stage. The adult fly resembles the blue-bottle flies. The 

 thorax is striped. The eggs, which number 250 or more, when 

 deposited in the nostrils or in wounds, develop into the screw-worm 

 larvae, which may, by going up into the frontal sinus, cause death. 



FIG. 74. Insects in which larval stage is important, i and 2, Insect and larval 

 forms of Dermatobia cyaniventris; A, ver macaque, B, Torcel or Berne; 4 and 6, 

 Insect and larva of Calliphora vomitoria; 5 and 7, insect and larva of Compso- 

 myia macellaria (screw worm). 



Sarcophagidae. 



These are known as "flesh flies." 



Sarcophaga carnaria. This is a grayish fly with 3 stripes on 

 thorax and black spots on each segment of the abdomen. It is vivi- 

 parous. The larvae gain access to nasal and other cavities and there 



