388 INSECTS WHICH DlSTHv WATER. 



with but few plants, constitute the vegetation of this 

 region. 



November 20th. — An eclipse of the sun, which I had 

 anxiously hoped to observe, with a view of determining 

 the longitude, happened this morning, and, as often took 

 place in this cloudy climate, the sun was covered four 

 minutes before it began. When it shone forth, the eclipse 

 was in progress, and a few minutes before it should 

 (according to my calculations) have ended, the sun was 

 again completely obscured. The greatest patience and 

 perseverance are required, if one wishes to ascertain his 

 position when it is the rainy season. 



Before leaving, I had an opportunity of observing 

 a curious insect, which inhabits trees of the fig family 

 (Ficus), upwards of twenty species of which are found 

 here. Seven or eight of them 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 natural- 

 ists 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 Cercopida, is known in Bngland as the frog-hopper 

 (Aphrophora spumaria), when full grown and furnished 

 with wings ; but while still in 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 climate, 

 especially of the graminacege, is not quick enough to yield 

 much moisture. The African species is five or six times 

 the size of the Knglish. 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 distil both by night 

 and day as much water as they please, and are more 



