452 INSECTS WHICH DISTILL WATER, 



cluster round a spot on one of the smaller branches, and there 

 keep up a constant distillation of a clear fluid, which, dropping 

 to the ground, forms a little puddle below. If a vessel is placed 

 under them in the evening, it contains three or four pints of fluid 

 in the morning. The natives say that, if a drop falls into the 

 eyes, it causes inflammation of these organs. To the question 

 whence is this fluid derived, the people reply that the insects 

 suck it out of the tree, and our own naturalists give the same an- 

 swer. I have never seen an orifice, and it is scarcely possible that 

 the tree can yield so much. A similar but much smaller homop- 

 terous insect, of the family Cercqpidce, is known in England as 

 the frog-hopper (ApkrqpAora sjpumarid), when full grown and fur- 

 nished with wings, but while still in the pupa state it is called 

 " CucJcoo-sjnt,''' from the mass of froth in which it envelops itself. 

 The circulation of sap in plants in our climate, especially of the 

 graminacese, is not quick enough to yield much moisture. The 

 African species is five or six times the size of the English. In the 

 case of branches of the fig-tree, the point the insects congregate on 

 is soon marked by a number of incipient roots, such as are thrown 

 out when a cutting is inserted in the ground for the purpose of 

 starting another tree. I believe that both the English and African 

 insects belong to the same family, and differ only in size, and that 

 the chief part of the moisture is derived from the atmosphere. 

 I leave it for naturalists to explain how these little creatures 

 distill both by night and day as much water as they please, and 

 are more independent than her majesty's steam-ships, with their 

 apparatus for condensing steam ; for, without coal, their abund- 

 ant supplies of sea-water are of no avail. I tried the following- 

 experiment : Finding a colony of these insects busily distilling 

 on a branch of the Ricinus communis, or castor-oil plant, I de- 

 nuded about 20 inches of the bark on the tree side of the insects, 

 and scraped away the inner bark, so as to destroy all the ascending- 

 vessels. I also cut a hole in the side of the branch, reaching to 

 the middle, and then cut out the pith and internal vessels. The 

 distillation was then going on at the rate of one drop each 67 

 seconds, or about 2 ounces 5^ drams in 24 hours. Next morning 

 the distillation, so far from being affected by the attempt to stop 

 the supplies, supposing they had come up through the branch 

 from the tree, was increased to a drop every 5 seconds, or 12 drops 



