416 INSECTS WHICH DISTIL WATER, Chap. XXI. 



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

 keep up a constant distillation of a clear fluid, winch, dropping to 

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

 under them in the evening, it contains tlnee 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 tins fluid derived, the people reply that the insects suck it out 

 of the tree, and our own naturalists give the same answer. I have 

 never seen an orifice, and it is scarcely possible that the tree can 

 yield so much. A similar but much smaller homopterous insect, 

 of the family Ccrcopidce, is known in England as the frog-hopper 

 (Aplirophora spumaria), when full grown and furnished with 

 wings ; but while still hi the pupa state it is called " cuckoo-spit" 

 from the mass of froth in which it envelops itself. The circulation 

 of sap in plants in our chmate, 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 in- 

 sects belong to the same family, and differ only hi 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 

 distil 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 abun- 

 dant 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 denuded 

 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 5i 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 



