TSETSE FLIES 



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agent in the spread of cholera, dysentery, infantile diarrhoeas and tropical ophthal- 

 mias as well as typhoid. 



In the Muscidae the antennae hang down in front of the head in three segments 

 and have an arista plumose to the tip. The first posterior cell is narrowed. There 

 are no bristles on abdomen except at tip. 



(I) Stomoxys, Hazmatobia and Glossina have a more or less elongated 

 proboscis adapted for biting. Stomoxys has delicate palpi, shorter than 

 the proboscis, and arista feathered only on the dorsal side with straight 

 hairs. Hasmatobia has club-like palpi about as long as proboscis and 

 arista with hairs dorsally and ventraUy. Glossina has thick set but 

 not clubbed palpi and an arista feathered on the dorsal side with 

 branching hairs. 



(II) Musca, Callipkora, Chrysomyia, Lucilia, and CordyloMa do 

 not have a proboscis adapted for biting. 



Stomoxys calcitrans. These greatly resemble the common housefly in size and 

 shape. They can be easily distinguished by the black, piercing proboscis extend- 

 ing beyond the head. There are longitudinal stripes on the thorax and spots on the 

 abdomen. The proboscis on examination will be seen to be bent at an angle near its 

 base. The palps are short and slender. The wings diverge widely. 



The female lays about 60 banana-shaped eggs in horse manure. These hatch 

 out in three days as larvae which turn into pupae in two or three weeks. After about 

 ten days the fly emerges. The genus Stomoxys includes vicious biters. This is the 

 fly which comes into houses before a rain, and which has given the common housefly 

 the reputation of biting before a rain. Stomoxys may be implicated in transmitting 

 surra (Trypanosoma evansi). 



It assumed great importance as a transmitter of poliomyelitis and 

 possibly of pellagra a few years ago views now discredited. 



The horsefly (H&matobia irritans) rarely bites man. In these the 

 palpi are much longer than in Stomoxys, being as long as proboscis. 

 These palps are also thick and spatulate. 



Glossina palpalis. This is the tsetse fly that is responsible for the 

 transmission of human trypanosomiasis (sleeping sickness). 



The tsetse fly is a small brownish fly about H inch long. The proboscis 

 extends vertically and has a bulb at its base. The arista is plumose only on the 

 upper side and the individual hairs are themselves feathered. The wings are carried 

 flat, closed over one another like the blades of a pair of scissors and project beyond 

 the abdomen. The most characteristic feature of the tsetse fly is the way the fourth 

 longitudinal vein bends up abruptly to meet the midcross vein and then curves 

 downward to run parallel with the third longitudinal vein. In Stomoxys, the wings 

 separate; in Hcematopota they just meet, and in Glossina they cross. Glossinae bite 

 chiefly in the daytime. 



The tsetse fly is much like Stomoxys, but has a branching of the feathering of the 



