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hand. Whatever may be the true explanation, it is certain 

 that oviposition takes place where there is an odour of 

 human or animal perspiration, because the parts of the body 

 which most frequently come in contact with the ground 

 are those in which tumours most usually occur ; oviposition 

 has also been known to take place on clothing saturated 

 with perspiration. The adult Tumbu fly is of a yellowish 

 colour, shading off to deep brown at the posterior end. 

 The larva (fig. 88) is barrel-shaped and almost completely 

 covered with minute spines in groups of two and three, 

 which aid in locomotion, and also probably by their irritant 

 action beneath the skin cause an increased flow of pus, on 

 which the larva feeds. 



Very similar in appearance to the Tumbu fly is Auch- 

 meromyia luteola (fig. 89), known in its larval state as the 

 Congo floor maggot. Although this fly has been known 

 for many years, it was thought, till recently, that its larva 

 formed a temporary home beneath the skin, after the manner 

 of the Tumbu fly. In 1904 Button, Todd, and Christy dis- 

 covered that the maggot possesses a habit, unique among 

 dipterous larvae, of sucking human blood. They observed 

 the natives of the Congo digging and scraping the cracks in 

 the mud floors of their huts and so collecting the larvae. 

 Only those floors were so treated on which the natives 

 were in the habit of sleeping, for where there are beds, or 

 the people sleep raised from the floor, the larvae are seldom 

 found. The female fly always lays her eggs on the ground, 

 selecting, if possible, places soiled with urine. 



The adult flies are about the size of a blue bottle, only 

 yellowish in colour and marked dorsally on the thorax 

 with black and brown stripes ; their legs are black. They 

 are shade-loving, spending most of their time resting in 

 the dark corners of native huts. Oviposition takes place 

 in two stages, separated by about a month, and, in all, 

 about eighty eggs are laid, always in the ground. The 

 larvae (tig. 90) are dirty white in colour and composed 



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