ach themselves to the long worm-like tongue of this animal, so that
the workers, on whom the prosperity of the termitarum depends, are saved
by the self-sacrifice of the fighting caste. The office of the termites
in the tropics seems to be to hasten the decomposition of decaying
vegetation. But they also work their way into houses, trunks, wardrobes,
and libraries. "It is principally owing to their destructiveness" (wrote
Humboldt) "that it is so rare to find papers in tropical America older
than fifty or sixty years."

Dragon-flies are conspicuous specimens of insect life on the Amazon. The
largest and most brilliant kinds are found by the shady brooks and
creeks in the recesses of the forest, some of them with green or crimson
bodies seven inches long, and their elegant lace-like wings tipped with
white or yellow. Still more noticeable are the butterflies. There is a
vast number of genera and species, and great beauty of dress, unequaled
in the temperate zone. Some idea of the diversity is conveyed by the
fact mentioned by Mr. Bates that about 700 species are found within an
hour's walk of Para, and 550 at Ega; while the total number found in the
British Islands does not exceed 66, and the whole of Europe supports
only 300. After a shower in the dry season the butterflies appear in
fluttering clouds (for they live in societies), white, yellow, red,
green, purple, black, and blue, many of them bordered with metallic
lines and spots of a silvery or golden lustre. The sulphur-yellow and
orange-colored kinds predominate. A colossal morpho, seven and a half
inches in expanse, and visible a quarter of a mile off, frequents the
shady glades; splendid swallow-tailed papilios, green, rose, or
velvety-black, are seen only in the thickets; while the _Hetaira
esmeralda_, with transparent wings, having one spot of a violet hue, as
it flies over the dead leaves in the dense forest looks "like a
wandering petal of a flower." Very abundant is the _Heliconius_, which
plays such an important figure, by its variations, in Wallace's theory
of the origin of species. On the Maranon we found _Callidryas eubule_, a
yellow butterfly common in Florida. The most brilliant butterflies are
found on the Middle Amazon, out of reach of the strong trade winds. The
males far outnumber the other sex, are more richly colored, and
generally lead a sunshiny life.

The females are of dull hues, and spend their lives in the gloomy
shadows of the forest. Ca