34 NATURAL HISTORY OF GLOSSINA PALPALIS 



It is of some importance, for reasons that will appear 

 later, to know whether palpalis does roam out of the 

 shade. There is no proof whatever that it wiU ever cross 

 the open water from one island to another. The little 

 islet Sanga, ofi the east end of Kome, has everything that 

 the fly can want, but for some reason it is unable to 

 establish itself there, and none can be found. Yet the 

 adjacent shores of the larger Kome abound with fly, and 

 it could very easily find its way across the few hundred 

 yards of water to Sanga, yet it does not. 



Palpalis, like morsitans, is at times a great nuisance, 

 for it will quietly sit on men's backs and thus be carried 

 a long way. Indeed, I have sometimes unwittingly taken 

 them back to my tent, where they remained, and rudely 

 bit me while having a bath ! On certain days, when it 

 is somewhat overcast but the sun shines through thin 

 clouds, they are perhaps at their worst, and are very 

 eager to bite, and will cling to one for long distances. A 

 very favourite trick is to alight on the under side of the 

 brim of one's hat and to quietly sidle round until the first 

 piece of skin free from hair is met with, when the proboscis 

 is lowered from its sheath and a sharp prick is felt on one's 

 temple. It is a curious fact that sometimes one is quite 

 unaware of being bitten, and may suddenly hear the 

 unmistakable heavy buzz of a bloated fly leaving after 

 a heavy feed ; at other times the prick is felt so sharply 

 that it might be produced by a needle. Presumably the 

 difference depends upon whether the fine point of the 

 proboscis finds a nerve end or not ! 



When a fly alights to feed it sidles about over the 

 skin and appears to be feeling for a soft place : when it 

 is satisfied the legs are slightly straddled out, and the 

 proboscis lowered from its sheath into a vertical position, 

 after which it gradually penetrates up to the bulb at its 

 base. It is then withdrawn slightly and the body of the 

 fly begins to swell with red blood. Almost at once the 



