MANUAL OF GENEEAL AGRICULTURE. 91 



sects in general. The biting type is found in cockroaches, 

 locusts, crickets, beetles, caterpillars, and larvae of prac- 

 tically 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 like 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 modifications have 

 proceeded in different ways in different groups, and are 

 so characteristic and peculiar for each group that it is 

 possible for the students of insects to recognize the group 

 to which any particular insect belongs by a study of its 

 mouth-parts alone. Bees and wasps have one type ; the 

 two-winged flies, as the mosquito, 

 horse-fly, and house-fly, another ; 

 the true bugs, as the cicada, stink- 

 bug, and squash-bug, another, and 

 the moths and butterflies still an- 

 other. 



Bees and Wasps. The mouth- 

 parts of these insects are usually 

 stated to be of the sucking type ; 

 they are in reality a combination B 



of the two. Mandibles, Fig. 14 md, PlG . i* Honey-bee. A, 

 with sharp cuttin gedges are head of honey-bee show- 

 usually present and fitted for in d mouth-parts extend- 

 biting, the upper lip is small * d; B > maxillae and la ' 

 and indistinct, the maxillae and bnm enlarged ' 

 labium, Fig. 14 A, have been greatly elongated and 

 find their greatest development in the honey-bee 

 If the maxillae, Fig. 14 mx, of the honey-bee are 

 compared with those of the locust, it is seen that the 

 lacinia is wanting and the maxillary palpus, Fig. 14 

 mp, is reduced to a mere tubercle. The greatest modi- 

 fication is found in the labium; the glossa, Fig. 14 g, in 



