Rural School Leaflet. 



1045 



15 mx, are situated just behind the mandibles and Hke the mandibles 

 move sidewise. Each maxilla bears on its outer end two finger-like 

 appendages: one the galea, Fig. 15 gl, is more or less spoon-shaped, 

 the other the lacinia. Fig. 15 Ic. pointed and with two teeth. 

 The galea and lacinia aid in holding the food in the mouth, where it can 

 be crushed by the mandibles and masticated. Each maxilla also bears 

 on one side a five-segmented feeler or palpus (plural palpi), the maxillary 

 palpus. The hypopharynx is a small tongue-like structure situated 

 in the mouth and attached to the inner surface of the lower lip. Fig. 

 15 hy. The lower lip or labium, 

 Fig. 15 lb, in the locust and other 

 insects consists of a single piece; it 

 is in reality a pair of jaws similar to 

 the maxillae grown together on the 

 middle line. The labium bears on 

 each side a three-segmented feeler or 

 palpus, the labial palpus. Fig. 15 Ip, 

 and at its apex two large, more or less 

 square flaps, the paraglossae, Fig. 15 pg, 

 and at the bottom of the slit between 

 the paraglossae, a minute projection, 

 the glossa. Fig. 15 g. The glossa in 

 the locust is rudimentary, but in many 

 biting insects it is as long as the para- 

 glossae, and, as will be seen later, 

 forms an important part of the mouth 

 of sucking insects. 



The mouth-parts of the locust illus- 

 trate well the form and arrangement 

 of the parts in the mouth of biting 

 insects in general. The biting type is found in cockroaches, locusts, 

 crickets, beetles, caterpillars, and larvae of practically all kinds. Certain 

 beetles, like the plum-curculio, have the front of the head produced 

 into a long snout or proboscis with the mouth-parts at the end of 

 the snout. The mouth-parts of such insects are Hke those of the 

 locust and are therefore fitted for biting. 



Mouth-parts fitted for sucking. — The mouth-parts of the locust have been 

 described in some detail because the mouth-parts of sucking insects have 

 all been developed by modification of the biting type. These modifi- 

 cations have proceeded in different ways in different groups, and 

 are so characteristic and peculiar for each group that it is possible 



Fig. 15. — The mouth-parts of a locust: 

 I, labrum; md, mandible; hy, hy- 

 popharynx; mx, maxilla; m.p, max- 

 illary palpus; gl, galea; Ic, lacinia; 

 lb, labium,; Ip, labial palpi; pg, 

 paraglossae; g, glossa 



