BUCCAL APPARATUS OF INSECTS. 97 



tible. Amongst the Bees, the Anthophora?, or solitary Bees, the 

 Humble Bees, and other Insects known by Zoologists under the 

 name of Hymenoptera, the luccal apparatus * presents an 

 arrangement, which is in some degree intermediate between these 

 two extreme states. The labrum and the mandibles much resemble 

 those of the gnawing Insects, and offer nothing very peculiar in 

 their form and structure (a and >, Fig.318); but the maxillae (c) 

 and the tongue (d) are greatly elongated ; and the former have 

 a tubular form, and inclose longitudinally the sides of the tongue ; 

 so that these organs, united into a bundle, form a canal that 

 serves for the passage of the food, always soft or liquid, by which 

 these Insects are supported. This tube is moveable at its base, 

 and flexible during the remainder of its length ; but it is never 

 rolled up, as we shall find amongst the Butterflies. The man- 

 dibles serve only to divide the materials, of which the Hymen- 

 optera make their nests ; or else to seize and put to death the 

 prey, whose juices these Insects suck. It is also to be observed, 

 that there exist within the buccal cavity other solid pieces 

 which are wanting amongst the gnawing insects ; and which 

 constitute valves destined to close the pharynx, whenever the 

 movement of deglutition is not going on. 



615. Amongst the Cicadae, the Bugs, and other insects of 

 the order Hemiptera, the apparatus for suction is 

 composed of the same elements ; but these present 

 a somewhat different arrangement. The mouth is 

 armed with a tubular and cylindrical proboscis, 

 directed downwards and backwards (Fig. 319), 

 and composed of a sheath inclosing four bristle- like 

 prolongations, or setae ; the sheath (, Fig. 320) 

 is composed of four joints, placed end to end, and 

 representing the labium or under lip : at its base 



Fro. 319.-Buo. . * A / . > i 



we perceive a conical and elongated piece, which 

 is analogous with the labrum ; lastly, the setw (b, c), which have 

 the form of fine threads, stiff and jagged at their points to be 



* The term luccal refers to that which belongs to the mouth ; and the above 

 expression is conveniently applied to denote the several parts collectively, which 

 altogether make up the mouth, in whatever way they may be arranged. 



