322 C. F. M. SWYNNERTON. 



jyodocoina (mudambasese) and Brachylaena rhodesiana (ipahJa). Tlie annually 

 burning grasses tend to disappear, the live carpet may become sparse or it may 

 become composed in part of tlie non-burning grasses that occur in the primary 

 forest of the same locality. Clumps and stretches of the handsome ribbon-like 

 izeya grass {Setaria mauritiana), beloved of buiTalos, also of ximomum (good shade 

 for brevipalpis) are exceedingly common, and thickets occur of such tall, more or 

 less herbaceous plants as Isoglossa mossanibicensis and the unpleasantly smelling 

 Mellera lohulata. Woody undergrow^th is usually more or less scarce excepting 

 when the wooding is under invasion by primary elements. 



In the simple coppice stages (PL xvii, fig. 1) these woods are highly attractive to 

 G. pallidipes ; in the older stages where the overwood is tall and heavy, as on the 

 Sitatonga base, and some underwood is present, they shelter G. brevipalpis. In 

 the Mtshanezi-Puizisi area especially a large proportion of the groves of this type 

 are of relatively low growth and are characterized by the presence of the very 

 beautiful climbing fern, Lygodium suhalatum, which carpets the ground and curtains 

 the trunks up to a considerable height, afiording low shelter and additional shade 

 where the shrub growth is poor. This variety of the type is perhaps more commonly 

 frequented by pallidipes than by brevipalpis. " Dense mixed secondary " occurs 

 here chiefly on the dolerite and, like Milletia bush, tends readily to be replaced 

 by primary elements (which are more suitable to brevipalpis) where it is in contact 

 with them. Thus Albizzia chirindensis and Piptadenia buchanani (umfomoti) 

 are at present sharing the dominance of the Mafusi rubber forest, and the shrub 

 growth shaded by them is already largely primary. The musara {Milletia) is rather 

 specially deciduous, and I have found relatively little dry season fly in this variety 

 of dense secondary excepting where it was under incipient primary invasion. 



(5). Bauhinia and Erythroxylon-Landolphia thickets. Two species of chigwendere 

 (Bauhinia galpini and B. petersiana), large and densely foliaged shrubs that lose 

 their butterfly-shaped leaves more or less late in the season, occur from the British 

 border to the Sitatonga Hills. B. petersiana continues to be present east of the 

 hills. They are found in every type of secondary wooding, especially on ant-heaps, 

 but in places they form almost pure coppice of their own. When well-grown and 

 in leaf, their coppice is more attractive to G. pallidipes. Where, however, the 

 Bauhinias occur isolated under higher shade, G. brevipalpis is attracted and rests 

 under their coils — for under these conditions they tend to assume the habit of 

 lianas. 



Low dense thickets of Erytkroxylon eynarginatiim, Pleuroridgea zanguebarica 

 and other erect shrubs, with a few rubber vines, have invaded (for the most part) 

 Pterocarpus wooding at high elevations on Mount Umtareni. I found no fly there, 

 for reasons probably of elevation and also of situation ; for between this and the 

 permanent fly-bush (Brachystegia) lower down the slopes lay a belt of highly 

 deciduous trees (formation 1, above). Lowland rubber forest (PI. xi) is not 

 essentially different. It also contains much of the Erytkroxylon, but the invasion of 

 Landolphia and other lianas has progressed further than on Umtareni and here fills 

 the thickets. The trees of the highly deciduous and other (Brachystegia) types that 

 have been invaded still in many places stand out above the new shrub gro^vth, 

 just as on Umtareni. I refer particularly to the Madanda forests, which I did not 



