IN SUMATliA. 227 



contribute to the nourishment of the young fruit and young 

 ovules ; and, in regard to the extrafloral nectaries, they go to 

 the development of the neighbouring organ." The chief 

 visitors and fertilisers of the S. javanica were white butterflies 

 (Pieridie) ; but I was unable to detect them sipping from the 

 honey-cups ; while species of wasps (Eumenes) that frequented 

 them occasionally came cautiously from below to sip the nectar, 

 but disregarded the flowers. These little cups were Twt confined 

 to the neighbonrhood of the flowers, but were arranged abun- 

 dantly on the leaves and on the stems of the plant as well. 



Here I was gratified to find abundance of the great Arums, 

 Amorphophallus titanum, of which I have already spoken ; * 

 with tubers of a greater size than any I had seen before, some 

 of them, indeed, being the largest yet recorded. The greatest 

 — measuring in circumference six feet six inches, and its stem 

 at the base two feet seven inches — formed, on its removal 

 from the ground, a load for twelve men. 



A striking feature also of the forest here was the enormous 

 results of the activity of earth-worms. The whole surface of 

 the ground was as rough and hummocky as a newly-ploughed 

 field. A tube four and a half inches in circumference and 

 eight inches high was often raised in a single night, and as, in 

 some places, there were as many as ten to twelve of these in 

 a square yard, it becomes evident what powerful agents they 

 are in the fertilisation of the soil, incessant as they seem 

 to be in their work of carrying up the soil from below and 

 laying it down on the surface, burying the rotting debris of the 

 forest. Insects were by no means common. Few bees, fewer 

 beetles, and hardly one of the finer forms of butterflies were 

 found except the magnificent Ornithoptera hrooheana, whose 

 favourite resort was the stones that cropped out above the 

 hot water, and which were of a temperature but little below 

 130° F. This butterfly has a bar of the richest lake dividing 

 the head from the thorax ; its blue-black wings are banded 

 on the upper side with the most sparkling metallic emerald, 

 and the under sides slashed with metallic green and blue, 

 which glittered and flashed in the sunshine, in whose brightest 

 hours alone they made their appearance. 



On the first favourable day, accompanied by one of the 

 * Supra, p. 175. 



