312 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



XXXIII. 

 GONOMETA POSTICA (Walker), 



BY J. E. SOMERVILLE, B.D. 



[Read 30th March, 1886.] 



In the spring of 1884 I jDaid a short visit to South 

 Africa. About the middle of February I was in the 

 Eastern province of Cape Colony, in the neighbour- 

 hood of Kingwilliamstown, the chief town of what 

 used to be called British Caffraria. Over a very 

 large part of South Africa one of the most common 

 trees is the Doornboom of the Dutch, the Mokohala 

 of the Kaffirs, the Acacia horrida of the botanist. 

 The tree, which occasionally attains a height of 

 25 or 30 feet, but is generally much less, covers 

 extensive tracts of barren and unoccupied land. Its 

 small pinnate leaves and scanty foliage do little to 

 protect the soil from the strong sunbeams. The tree, 

 as its name indicates, is very thorny; but the size 

 and number of the thorns vary much. In some 

 places the trees are comparatively free, in others 

 they are covered with enormous spikes four inches 

 or more in length. Previous to my visit there had 

 been months of drought, and things had a inarched 

 look. To add to the forlorn aiDpearance of the 

 country, the Acacia trees had suffered from the 

 ravages of an insect, whole branches being stripped 

 and bare. On examining the trees they were found 

 to be attacked by a hairy caterpillar of gigantic 

 dimensions. The specimens, which at the time were 

 mostly full-grown, were above four and a half inches 

 long, of a rich deep black colour, with a few 

 scattered white hairs, the head and feet being 

 reddish brown. I found them extending over a 

 <jonsiderable area from the Kei river on the east to 



