512 FLY MAGGOTS AND MYIASIS 



on the floors of native huts. The fly is said by Roubaud to make 

 a furrow in the dust with her abdomen while running on the 

 ground, feeling for breaks or cracks in which to deposit her eggs. 

 Having found such a spot she forces her abdomen into it and 

 deposits usually a single egg, then seeks a new crack, deposits 

 another egg, etc., until the whole number of from 30 to 80 eggs 

 has been disposed of. The eggs, the development of which is 

 favored by dry surroundings, hatch in a few days. Within four 

 or five hours after emergence the larvae are ready to suck blood if 

 opportunity presents itself, but they are able to live nearly a 

 month without food, remaining buried an inch or so in the dust 

 of floors. They can always be collected by digging with the point 

 of a knife in cracks in the earth under sleeping mats. Roubaud 

 collected 100 larvae in half an hour, many of them filled with 

 blood, in a hut where a dozen children slept. 



The maggots (Fig. 244B) are dirty-white creatures, much 

 wrinkled in appearance, but otherwise quite like the larvae of 

 houseflies. The tapering anterior end of the body is provided 

 with a pair of black hooks to aid in piercing the skin of the host, 

 and has retractile sucking mouthparts. The thick leathery skin 

 and the position in a crack in the ground protects the larva from 

 injury when stepped on by the bare feet of the natives. The 

 body is beset with rings of spines which aid in the wriggling 

 method of locomotion. The maggots are inactive in the day- 

 time, but come forth at night to suck the blood of sleepers, biting 

 . them usually on the side of the body next to the ground. The 

 bites are less irritating than those of mosquitoes, and according 

 to Roubaud the bites of 20 larvae at once produced no inflam- 

 mation or itching. 



Under ideal conditions the larvae pass through two moults and 

 go into the pupal stage in 15 days, but this may be extended to 

 about two and one-half months under unfavorable conditions, 

 such as low temperature and irregular food supply. The pupal 

 stage lasts about 11 days. The adults do not begin laying eggs 

 until about two weeks after emergence. The whole life cycle, 

 therefore, from egg to egg, is about one and one-half months 

 under favorable conditions. 



The Congo floor maggot is not known to attack any animals 

 but man in nature, though a closely allied maggot, Chceromyia, 

 lives in the burrows of the wart hog and other hairless mam- 



