AXNULOSA INSECTA. 



61 



In the butterflies, the upper lip and mandibles are un- 

 developed; the maxillse are very long, and form, by their 

 coalescence, a suctorial tube, 

 which is coiled up under the 

 head when not employed in 

 sucking the juices of flowers. 

 When coiled up, the tube is sur- 

 rounded by the labial palpi, 

 which, in these insects, take 

 the form of two hairy cushions. 



The mouth, in the bee, is 

 adapted both for biting and 

 suction. The labrum and man- 

 dibles are of the ordinary form, 

 and are employed in the manu- 

 facture of the honeycomb. The 

 maxillae and the labium are con- 

 verted into a long tube, which 

 is used in sucking the honey 

 which forms the food of these 

 insects. This tube cannot be 

 coiled up as in the butterflies. 



In the bugs and plant lice 

 the jaws are transformed into 

 lancets. These are enclosed in 

 the labium, which takes the 

 form of a tubular sheath. In 

 the flies (Dipt era) the jaws 

 sometimes take the form of 

 bristles, and sometimes 

 lancets. 



The mouth leads by an oesophagus into a membranous 

 and generally folded stomach, termed the crop. From 

 this, in the masticating insects, it 'passes into a second 

 stomach, called the gizzard, which is furnished with 

 muscular walls and plates of chitine, for grinding the food. 

 Then follows the true digestive stomach, which is suc- 

 ceeded by an intestine of variable length, being short in 



FIG. 23. DIGESTIVE APPARATUS OP 



THE CRICKET. 



a, head and its appendages ; &c, 

 salivary glands ; d, antennae ; e, 

 gizzard, preceded by the O3sophagus 

 bearing the crop ; /, sacs connected 

 with the gizzard; gh, true diges- 

 tive stomach ; i, intestine ; k, Mal- 

 0f phigian canals. 



