52 NATURAL HISTORY OF GLOSSINA PALPALIS 



larva destroys the Glossina. It has since been found out 

 that the Chalcid Syntomosphyrum destroys not the 

 Glossina but the Mutilla, which has itself destroyed the 

 Glossina, so that this Chalcid works on the side of and 

 not against Glossina. 



When the adult fly has broken through the end of the 

 pupa case and pushed its way up through the loose soil 

 covering it, it seeks for a stem up which to crawl so that 

 it may rest with the wings hanging vertically downwards 

 while they stretch and dry. At this time the fly is a 

 soft white juicy morsel, and any ant that happened upon 

 it would find a pleasant meal. But the fly seems to 

 realize its danger, and is very much on the alert. More- 

 over, its legs are surprisingly firm, although it appears 

 so weak : I have several times watched newly hatched 

 specimens resting on a pebble until the wings had har- 

 dened, and if an ant came near enough to be dangerous 

 they would quickly sidle away. 



An interesting insect, the " ant lion," makes its conical 

 pits in the dry loose sand used as breeding grounds by 

 Glossina, and lies in wait at the bottom ready to seize 

 such insects as fall into the pit. Since these pits are often 

 very numerous in the soil over which the freshly emerged 

 fly has to scramble, the helpless insect must sometimes 

 fall into one of these pits and be devoured before the 

 wings have expanded, and I have actually seen one as 

 it scrambled along fall down a pit. But the " ant lion " 

 had either pupated or was not hungry, for it paid no 

 attention and the fly scrambled out again. 



These pits are often so abundant in the very spots 

 selected by the fly for its larvae to burrow in that I think 

 it cannot be uncommon for the freshly hatched flies to 

 fall in and be devoured. 



Much time has been spent in observational work on 

 possible enemies of the adult fly. On Damba Island 

 forty-four insectivorous birds feeding in the fly belt were 



