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 the grasshopper's range of vision compare with that of the crawfish?

Are the antennæ flexible? What is their shape? Position? Are they segmented? Touch an antenna, a wing, a leg, and the abdomen in succession. Which seems to be the most sensitive to touch? The antennæ are for feeling; in some species of insects they are also the organs of hearing.

The mouth parts of a grasshopper are highly specialized. They should be compared with the mouth parts of a beetle shown in Fig. 113, since the mouth parts of these two insects correspond closely. If the grasshopper is fed with a blade of fresh grass, the function of each mouth part may be plainly seen. It is almost impossible to understand these functions by studying a dead specimen, but a fresh specimen is much better than a dry one.

—a,.

b, gizzard; d, intestine; c, biliary vessels. See Fig. 127.

The upper lip, or labrum, is seen in front. Is it tapering or expanded? In what direction is it movable? The dark pointed biting jaws (mandibles) are next. Are they curved or straight? Sharp or blunt pointed? Notched or smooth? Do they work up and down, or sideways? The holding jaws (maxillæ), each with two jaw fingers (maxillary palpi) are behind the chewing jaws. Why? The lower lip (labium) has a pair of lip fingers (labial palpi) upon it. The brown