432 VETEEINAEY HYGIENE 



many parts of Africa, and is capable of causing immense 

 loss by inoculating animals with the Trypanosoma Brucei, 

 obtained from wild animals which are immune to the disease. 

 Whole districts of domesticated animals may in this way be 

 cleared off, for the disease attacks the horse, mule, ass, ox, 

 and is usually fatal, though a few oxen recover. 



The fly, which during its flight emits a high-pitched 

 buzz, is greyish-brown, and about half an inch in length 

 with a prominent proboscis. The position of the wings at 

 rest, viz., close together, and lying flat over each other Hke 

 the blades of scissors, distinguishes the Tse-tse from all 

 other flies. 



The fly attacks suddenly and in the most determined 

 way ; it presses in the proboscis causing slight pain ; in a 

 few seconds the sucking is over, and the previously collapsed 

 abdomen is now distended and of a cherry colour. 



Another species, Glossina palpalis, has recently been dis- 

 covered as the carrier of the trypanosome which produces 

 the sleeping sickness of Uganda. 



With Tse-tse flies both sexes are blood-suckers ; further, 

 unlike many of the family they belong to, they are repelled 

 and not attracted by ordure. 



Of Blue-bottles or meat-flies there are two species ; both 

 lay their eggs on decaying animal matter, and do not 

 attack animals. 



Of Green-bottles there are two species, viz., Lucilia Ccesar 

 and Lucilia sericata. Both are bright green in colour, 

 though the latter has a bluish sheen absent in the former. 

 These flies lay eggs in wounds and putrefying matter, 

 L. sericata being responsible for the disease in sheep known 

 as ' maggot.' 



Maggot in Sheep. — This occurs particularly with young 

 and weakly sheep ; those suffering from diarrhcea (by which 

 soiling of the wool occurs) are especially liable to attack. 

 L. sericata does not attack sheep as an absolutely necessary 

 part of its life cycle, but because the filthy and offensive 

 state of the fleece proves attractive, more particularly if 

 any neglected sore exists. 



Digitized by Microsoft® 



