the Butterflies of the White Nile. 15 
visit its snake-like branches were leafless and flowerless. 
Several days out of our twenty-four were spent in the 
Sadd.* Here the mass of the vegetation for many miles 
at a stretch was made up of the dark green Papyrus 
(Cyperus) antiquorum with its beautiful umbels six feet 
across, and of “ tim sif,”’ or “‘ mother of wool ”’—Vossia 
procera—a reed-like plant, together with the more familiar 
Phragmites communis. Of smaller plants growing beneath 
the Papyrus at the water’s edge a yellow composite and 
a blue-purple Convolvulus or Ipomaea were the commonest. 
The first “ Candelabra” Huphorbia, striking trees nearly 
twenty feet high, were seen on the island of Hillet al- 
Nuwér [Lat. 8° 13’ N.]. At Bér [Lat. 6° 13’ N.], my 
attention was called to the singular Kigelia aethiopica, Decr., 
a tree belonging to the Nat. Ord. Bignoniaceae, which has 
flowerstalks many feet in length from which hang the 
large rich brown-purple flowers and cucumber-like fruits, 
the latter a foot long. At Rejaf[Lat. 4° 45’ N.] a yet more 
tropical-looking plant was the Adeniwm coetaneum, Stapf. 
[Nat. Ord. Apocynaceae], with its absurdly thick stems, 
fleshy emarginate leaves, and clusters of showy bright- 
red waxy flowers. Palms were rarely seen. Doubtless 
this somewhat monotonous vegetation largely explains 
the restricted Butterfly Fauna. 
The practice of burning the rank vegetation of the 
Sadd, must have a very destructive effect upon insect life. 
The numerous semi-calcined shelis of such Gasteropods 
as Burtoa and Limicolaria—genera frequenting trees or 
bushes—which are seen in many localities, prove that these 
fires carry their destruction beyond the grassy areas on 
which antelopes, giraffes and elephants still roam even 
within sight of the steamer. 
The circumstance that nearly every tree and shrub met 
with is more or less prickly tends greatly to protect butter- 
flies from the collector’s net. Near Ad-Duwém I came 
across a grass even worse than the Indian “ spear-grass,”’ 
for its prickly awns at a touch converted the net into a 
tangled mass, which required some minutes to unravel. 
Fortunately its distribution appears to be restricted to 
a very small area. 
Shortly, the district to be dealt with includes Khartim 
[Lat. 15° 37’ N., Long. 32° 31’ E.] and the country adjacent 
to the banks of the White Nile to Lake Né6 [Lat. 9° 30’ N.]; 
* The correct spelling : pronounced Sudd. 
