172 JOURNA L, BOMBA Y NA TURAL HISTORY SOCIETY, Vol. XV. 



secondly, as on the kind of mouth parts present depends the nature of the 

 damage Insects are able to commit, and the methods which can be em- 

 ployed to attack them. The biting mouth consists of an upper lip, the 

 ' labrum,' which forms the front of the mouth and covers the base of the 

 * mandibles' or biting jaws. Below the mandibles we have a second pair 

 of jaws or 'maxillae' of more complicated structure and made up of a 

 number of more or less well-marked pieces which vary considerably in 

 form and shape according to the food and habits of the insect. Attached 

 to each maxilla is a ' palpus ' or feeler, which often has organs of sense. 

 The mandibles cut and tear the food, the maxillae break it up still further 

 and then deliver it to the ' labium ' or lower lip, which also helps in mixing 

 the food. The labium closes the mouth opening beneath, forming its floor, 

 so to speak. It is less complex than the maxilla, and it may consist of only 

 a single piece or plate, but like the maxilla it is furnished with a pair 

 of palpi or feelers. Fig. 3 shows two designs of a biting mouth. In- 

 sects provided with this 

 form of biting mouth 

 are always susceptible to 

 being poisoned through 

 their food, i.e., they may 

 be reached by poisons 

 which will be taken inter- 

 nally. Of the sucking 

 mouths there are several 

 varieties functionally 

 quite diverse and indicat- 

 ing differences of habit. 

 In the butterfly and moth 

 we have a flexible tube, 

 coiled like a watch spring 

 under the head between 

 the labial palpi. Mandi- 

 bles are absent and other 

 parts aborted. This is 



used for sucking honey, FlG- 3._ Hea (l and mo^th^arts of a Ground Beetle 



&C, and therefore these (Carafots~) enlarged. A, from above ; B. 



■ I, r from below, a. labrum ; b, mandible ; /, 



insects are incapable of maxi]la with ' palpi; ,. e \ labium witb 



inflicting damage in this palp, e. 



stage of their existence. A different form of sucking mouth is present in 



