1832,] SWARM OF ANTS. 85 
and others returning, burdened with pieces of green leaf, often 
larger than their own bodies. 
A small dark-coloured ant sometimes migrates in countless 
numbers. One day, at Bahia, my attention was drawn by ob- 
serving many spiders, cockroaches, and other insects, and some 
lizards, rushing in the greatest agitation across a bare piece of 
ground. A little way behind, every stalk and leaf was blackened 
by a small ant. The swarm having crossed the bare space, 
divided itself, and descended an old wall. By this means many 
insects were fairly enclosed ; and the efforts which the poor little 
creatures made to extricate themselves from such a death were 
wonderful. When the ants came to the road they changed their 
course, and in narrow files reascended the wall. Having placed 
a small stone so as to intercept one of the lines, the whole body 
attacked it, and then immediately retired. Shortly afterwards 
another body came to the charge, and again having failed to 
make any impression, this line of march was entirely given up. 
By going an inch round, the file might have avoided the stone, 
and this doubtless would have happened, if it had been originally 
there: but having been attacked, the lion-hearted little warriors 
scorned the idea of yielding. 
Certain wasp-like insects, which construct in the corners of the 
verandahs ‘clay cells for their larve, are very numerous in the 
neighbourhood of Rio. These cells they stuff full of half-dead 
spiders and caterpillars, which they-seem wonderfully to know 
how to sting to that degree as to leave them paralysed but alive, 
until their eggs are hatched; and the larve feed on the horrid 
mass of powerless, half-killed victims—a sight which has been 
described by an enthusiastic naturalist * as curious and pleasing ! 
I was much interested one day by watching a deadly contest 
between a Pepsis and a large spider of the genus Lycosa. ‘The 
wasp made a sudden dash at its prey, and then flew away: the 
spider was evidently wounded, for, trying to escape, it rolled down 
a little slope, but had still: strength sufficient to crawl intoa 
thick tuft of grass. The wasp'soon returned, and seemed sur- 
* In a MS. in the British Museum by Mr. Abbott, who made his observ- 
ations in Georgia; see Mr. A. White’s paper in the ‘ Annals of Nat. Hist.,’ 
vol. vii. p. 472. Lieut. Hutton has described a sphex with similar habits in 
India, in the ‘ Journal of the Asiatic Society,’ yol. i, p. 555. 
