144 



ScHWETZ (J.)- A Comparative Study of the Habits of Glossina brevi- 

 palpis, Newst., G. fvsca, West., and G. paUidipes, Aust. in the 

 Belgian Congo. — Ann. Trop. Med. Parasit., Liverpool, xi, no. 4, 

 nth May 1918, pp. 365-398, 1 map & 1 chart. 



The author's summary of this paper is as follows : 



The five important tsetse-flies, G. brevipalpis, G. fusca, G. paUidipes, 

 G. morsitans and G. palpalis, select tree-trunks, the larger branches 

 of trees and creepers for resting purposes. In regions where they 

 occur, G. brevipalpis and G. pallidipes are not restricted to limited 

 areas or belts, but, like G. morsitans, are found uninterruptedly, except 

 in large clearings, over vast stretches of country. 



The habits of G. pallidipes are intermediate between those of 

 G. brevipalpis and G. morsitans. Like G. brevipalpis, G. pallidipes 

 hovers over the ground when active, and is usually so only at certain 

 fixed times, especially between 3 p.m. and 5 p.m. (4 to 6 p.m. in the 

 case of G. brevipalpis), the maxinuim activity being reached about 

 4 p.m. The habits of G. pallidipes, however, are less well-defined 

 than those of G. brevipalpis, and it not only laites more often than 

 the latter, but is not uncommonly seen on the wing in very small 

 numbers throughout the whole afternoon and occasionally in the 

 forefioon. Of the examples of G. p)allidipes captured w^hen active, 

 only about 15 per cent, were females. In those regions where G. brevi- 

 palpis occurs it accomodates itself to all types of arborescent vegeta- 

 tion, forest, park- land and wooded savannah, but G. pallidipes, Uke 

 G. morsitans, does iK)t inhabit forest. G. fusca occurs in forests only. 

 As the region where these observations were made (northern Katanga, 

 notably the districts between the Lualaba and upper Lomami rivers) 

 consists of park-land and savannah, the forest only being represented, 

 usually along rivers and streams, by belts of varying width, it is 

 evident that in this region G. fusm only occurs in some- 

 what Hmited areas. Further, these areas are still more restricted 

 owing to the fact that this species only inhabits moderately dense 

 forest belts of a certain width (200 to 300 yards). But contrary to 

 what has been thought hitherto, where G. fusca does occur, it is not 

 at all uncommon, and sometimes is even abundant. It has however 

 peculiar habits ; it does not fly during the day, like G. morsitans and 

 G. palpalis, and does not hover over the ground at definite times like 

 G. brevipalpis and G. pallidipes, but always remains motionless on 

 tree-trunks and creepers. Occasional specimens, usually one or two, 

 are sometimes attracted by men and animals passing by. These 

 may make their appearance at any time of the day, but prefer the 

 cooler hours, e.g., early in the morning or more often late in the evening. 

 G^./wscaalsohasadefiniteperiodof activity, namely from 7 to 8 p.m., 

 or one to two hours after simset, and if a haimt of the fly be passed 

 during this time, numerous attacks are sure to be made. 



Females of G. fusca, unlike those of G. brevipalpis and G. pallidipes, 

 are commonly found, and form nearly 50 per cent, of the specimens 

 captured, whether the flies be taken on the wing or resting on trees, 

 etc. Since forest belts usually occur near water, it is in the neighbour- 

 hood of the latter that G.fuscxi is generally found, though it also occurs 

 in forest belts where there is no water in the immediate vicinity, 

 and may even be found in forest a few kilometres distant from the 



