XVl] GLOSSINA LONGIPALPIS 275 



of this species are those of Roubaud in Dahomey. In this 

 region G. longipalpis is found near the streams and large rivers. 

 The separation of the sexes is well marked, the males being 

 met with only in the tufts of bushes along the edge of the 

 forest near the water courses, while the females are found in 

 open clearings where there are acacias and mimosas. The fly 

 is especially abundant during the rains, but seems to disappear 

 almost completely in the dry season, especially after the bush 

 is burnt. During the rainy season the fly, extends its range 

 very considerably and may be found more and more outside 

 its usual haunts, individuals occurring in the savannahs far 

 from any water course. The period of the north-east wind 

 (Harmattan) is very unfavourable to them. 



G. longipalpis feeds mainly on wild mammals, accompanying 

 them in their movements ; it especially frequents paths recently 

 trodden by hippopotamus and elephant. 



Reproduction. G. longipalpis has never been observed to 

 copulate in captivity. Moreover, it is very susceptible to the 

 influence of physical conditions, a temperature of 35°-37° C, 

 with either saturated or dry air, interfering with reproduction. 



At 25° C, Roubaud found that the females deposited 

 larvae at intervals of about ten days, and the pupal stage, at 

 an average temperature of from 24° to 25° C, was found to 

 last from 26 to 35 days. The pupae hatch out all the year 

 round, including the cold season, and the diminution of flies 

 in the dry season cannot be explained by the assumption that 

 during this period the pupal stage is prolonged. 



G. LONGIPALPIS and Disease. 



This species is a most important carrier of animal trypano- 

 somiasis. Thus in Dahomey, Bouet and Roubaud found 

 that the wild flies were frequently naturally infected with 

 T. dimorphon, and that on the Oueme River a very large pro- 

 portion of the flies were infected with T. pecaiidi. G. longipalpis 

 is said to be the " host of choice " for this latter trypanosome. 



In addition, this species is an efficient intermediate host for 

 T. cazalhoui. 



18—2 



