THE FLIES THAT CAUSE MYIASIS IN MAN 



73 



septic exudations and blood from wounds. The larvae hatch in 18 to 

 24 hours ; after feeding near the surface until the first molt, they burrow 

 deeply into the living tissues, which become liquefied with their ad- 

 vance. The larvae mature in about 6 days, then drop to the ground to 

 pupate within the soil. The duration of the pupal stage varies accord- 

 ing to the season ; the short winter in the cooler parts of its range is 

 probably spent in this stage. The biotic potential of the fly is enor- 

 mous ; a female may produce 500 to 600 eggs in her lifetime, and there 

 may be eight or more generations a year. 



This is the most important myiasis-producing calliphorid of the Old 

 World; according to Cuthbertson it ranks second in importance to 



Figure 35. — Chrysomija hezziana: A, Larva; B, cephalopharyngeal skeleton; C, 

 anterior spiracle, much enlarged ; D, spines, much enlarged ; E, posterior end, 

 showing spiracles; F, pupa. (After Cuthbertson (32 J.) 



the tsetse flies as a cattle pest in Africa. Cattle are the chief hosts, 

 although it frequently attacks man as well as various domestic and 

 wild mammals. 



An open wound is usually chosen for oviposition : a large foul-smell- 

 ing one may contain several batches aggregating 800 or 1.000 eggs. 

 The evidence indicates that, in spite of statements to the contrary, 

 larvae cannot enter healthy, unbroken skin, although a very small 

 lesion, such as a tick bite, may permit entrance. Diseased body 

 openings, bruises, or tumors produced by elephantiasis may invite 

 oviposition. 



The larvae may attack wounds on various parts of the body : in man 

 infestation of head wounds seems most frequent. Because of the num- 

 ber of the larvae and the depth of their penetration, the results may 

 be serious. Infestation of the nose, mouth, ears, eyes, and frontal 

 sinuses are not uncommon in India, and may result in the loss of an 



