XXI. SOME SIX-LEGGED INSECTS
One of the great divisions into which the insects are divided relates to their possession of six legs (Fig. 180). This includes a marvelous array of creatures. Among them we find the singular little glacier flea (Fig. 181) and the springtail, a prodigious jumper (Fig. 182). The latter is found in damp places, and when touched will release a forked spring which is held in place by a hook, and this sends the insect flying into the air like an acrobat. These humble little creatures present a strange contrast to the lace-winged insects which are among the most beautiful of the tribe.
Fig. 180.—A six-legged insect.
The May flies (Fig. 183) are well known for the wonderful exhibitions they sometimes make, the air being filled with them, a joyous, beautiful throng, destined to live but a few hours. In South America they occur in such vast numbers that they are collected and used as guano. The young pass through a strange change, having little resemblance to the parent, and live in the water, where they breathe by means of several plumelike gills.
Fig. 181.—Glacier flea.
Fig. 182.—Springtail.
