282 INSECTS. 
said to be imperfect. The eyes of insects are either 
compound, composed of nmnerous lenses, amounting in 
certain butterflies to thirty thousand, or simple, called 
stemmata^ the latter alone being found in the larvae, 
although in some of the beetles the larvae have eyes in 
the head and tail both. They are often long in matur- 
ing ; one species of locust, as is well known, remains 
seventeen years before coming to perfection, and many 
other families continue several years as larvae. Some of 
the larvae live in the earth, some in wood, and others 
under water ; some hide themselves in a cocoon ere their 
metamorphose is effected, others build houses of stones 
or sticks, others have no protection ; but all are wonder- 
ful. One swims upon the water, another walks upon its 
surface, a third crawls along at the bottom, although the 
majority live upon dry land. In defence they use a 
sting, simulate death, eject a poisonous liquid, or emit 
an offensive smell. The eggs mature in the running or 
stagnant water, in the ground, in the limbs of trees, in 
the foliage and stems, or in the fruit. Grasshoppers in 
the East, grubs among savages, snails among French- 
men, ants among Brazilians, locusts among prophets, 
and, if all reports are true, certain minute parasites 
among Italians, have furnished pleasing and nutritious 
food. 
But of all the marvels of insect life, that which is least 
consonant with nature and least credible to human 
understanding, is the fact that they appear spontaneously. 
"Why should a few drops of rain in a dusty road produce 
animalculae never seen before ? Why should a little per- 
manent dirt originate two distinct parasites, according as 
