INSECTS
below the mouth. Behind the mandibles is a pair of maxillae (B, Mx) of more complicated form, fitted rather for holding the food than for crushing it. Following the maxillae is a large under lip, or labium (Lb), having the
Fig. 67. Lengthwise section of a grasshopper, showing the general location of the principal internal organs, except the respiratory tracheal system and the organs of reproduction
An, anus; Ant, antenna; Br, brain; Cr, crop; Ht, heart; Int, intestine; Mal, Malpighian tubules; Mth, mouth; Oe, oesophagus; SoeGng, subnesophageal ganglion; Vent, stomach (ventriculus); VNC, ventral nerve cord; W, wings
structure of two maxillae united by their inner margins. A broad flap hangs downward before the mouth to form an upper lip, or labrum (Lm). Between the mouth appendages and attached to the front of the labium there is a large median lobe of the lower head wall behind the mouth, known as the hypopharynx (Hphy).
Insects feed, some on solid foods, others on liquids, and their mouth parts are modified accordingly. So it comes about that, according to their feeding habits, insects may be separated into two groups, which, like the fox and the stork, could not feed either at the table of the other. Those insects, such as the grasshoppers, the crickets, the beetles, and the caterpillars, that bite off pieces of food tissue and chew them, have the mandibles and the other mouth parts of the type described above. Insects that partake only of liquids, as do the plant lice, the cicadas, the moths, the butterflies, the mosquitoes and other flies, have the
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