INTRODUCTIOX. 



XXV 



the joints l)ot\veen the scape and the chih are termed the funicuhts : all 

 such elbowed antennae are termed (leniculate : the elongate first joint or 

 scape, although not in so marked a degree as in the Khynchophora, is 

 found in other Coleoptera, e.g. Cri/ptobium among the Staphylinidae, &c. 



The trnphi or mouth orr/ans. — The Coleoptera belong to the mandi- 

 bulate as opposed to the haustellate insects, that is to say they are 

 furnished with horizontally moving jaws for seizing and masticating 

 their food ; the haustellate insects, on the other hand, like the Lepid- 

 optera, obtain their food by suction by means of a tube or trunk : if 

 we examine the underside of the head of any beetle Ave shall find that 

 nearer to or further from the front there is a suture : this suture is 

 called the mental suture, or more generally the gular stiture ; this last 

 term, however, is erroneous, as the gular sutures proper lie at the sides 

 between the opening of the mouth and the mental suture ; if with a needle 

 (ground down to an edge on a fine hone and fixed by sealing-wax into a 

 piece of wood such as a match stem) we divide this mental suture, and 

 in the case of a larger insect the gular sutures proper as well, we shall be 

 able to separate and examine in detail all the mouth organs : it is very 

 necessary that all students of Coleoptera should be al:)le to dissect these, 

 at all events to a certain extent ; for, although classification by the 

 external skeleton and other characters is more and more taking the place 

 of classification by the trophi, yet at present these still play a very con- 

 siderable part in the classification of the Coleoptera, and they must 

 always be considered as at all events of very great secondary importance ; 

 unless they are dissected out, it is impossible to examine them properly, 

 and therefore unless a student is able to dissect he will not be able in 

 many instances to rightly determine the genera, much less the species : 

 a little practice is all that is required : as a rule, wdreu the mental suture is 

 severed, the mentum, labium and maxillajmay 

 at once be removed in one piece ; the man- 

 dibles may be examined without removal : 

 if, therefore, the mouth parts are carefully 

 dissected and the insect again remounted, 

 it will to all intents and purposes be still 

 perfect. 



Above the mouth there is usually visible a 

 small piece which is called the lahrum or up- 

 per lip ; it is usually, but not always, more or 

 less membranous ; it either projects wholly 

 or partially beyond the clypeus, or it may be 

 completely hidden behind the cl^'peus and 

 be connate with it ; useful characters are 

 sometimes found in its shape, whether emar- 

 ginate, truncate, projecting, &c. IJelow the 

 labrum come the large jaws or mauLUhJcs, 

 which are the most powerful of the mouth 

 organs ; they vary much in shape accordin 



7. 



of D. marginalis, upper 



(7. Labruni. 5. Clypeus. e,d. M;in- 



dibles. e. Kyes. f. Baseof :iiitcii- 



ua3 g. Voitox. h. Occiput. 



to the food of the insect : 



