NATURAL HISTORY OF SOUTH AFRICA 



(Estrida) lay eggs on the hair of horses and other 

 large animals. These eggs are licked off and 

 swallowed by the animals, and the larvae which hatch 

 from them live as parasites in their hosts' stomachs. 

 The larvae are known as bots. The larvae of some 

 species live in the nasal and ear cavities of large 

 animals, and cause their victims acute distress. 



The warble flies (Hypoderrnd) are another pest to 

 large animals. The female punctures the skin of her 

 host and lays an egg. A grub hatches from the egg 

 and passes its larval span of life beneath the skin of 

 the animal, living on the juices of its host all the time. 

 When adult it burrows out, drops to the ground, and 

 changes into a chrysalis. The grub of the botfly, 

 when adult, passes out of its host with the stallings, 

 and also changes into a chrysalis on the ground. 

 Partridges, guinea-fowls, starlings, and some other 

 species of birds break up the droppings of animals 

 and eat these grubs and any worms or other noxious 

 forms of life they might contain. By scattering the 

 excrement of animals they also render excellent service 

 by preventing other species of flies from breeding in 

 it ; and by exposing it to the drying heat of the 

 sun, any eggs of parasitic pests it might contain are 

 shrivelled up and destroyed. 



The tse-tse flies of the genus Glossina inoculate 

 man with sleeping sickness, and domestic animals 

 with a disease known as nagana or tse-tse fly disease. 

 The maggots are produced alive, and are full-grown 

 when born. They are usually deposited in damp, 

 loose, loamy, leaf-strewn soil under bushes, where 



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