OF DIGRSTION. 349 



they masticate small insects with their maxillae, swallowing them 

 gradually, holding their bodies the while with their mandibles. The 

 hard parts, namely, the wings and feet, they drop after they have 

 devoured the soft body. They want the proventriculus, and therefore 

 the maxillae completely comminute all their food. The Dictyotoptera 

 mallophaga likewise masticate, as, according to Nitzsch, they feed upon 

 the down of feathers ; they want the proventriculus, but they have a 

 large crop, in which their swallowed food softens for a time and is 

 prepared for digestion. 



Upon reducing the different modes of mastication of insects to one 

 general view we shall find it to present the following: 



Mandibulate insects devour, 



1. Firm materials, which they bite off piecemeal, and which are 



masticated. 

 . Merely in the mouth. Libellulce. 



b. Less in the mouth, but more in the proventriculus. Cara- 



bodea, water beetles, and StaphylinL 



c. Both in the mouth and proventriculus. Grylli. 



d. Neither in the mouth nor in the proventriculus, as the latter 



is wanting, whereas the creature bites off but small pieces, 

 which can be swallowed entire. The caterpillars of the 

 Lepidoptera; the Chrysomelce. 



2. Fluids or substances which easily dissolve. 



a. They are swallowed as separated by the mandibles. Ontho- 



p/iagous Petalocera, Pcltodea, Capricorns. 



b. They are lapped up by the pencillate maxillae and sucked 



out in the mouth. Lucani, Tenthrcdonodea, Ichneumons. 



218. 



Many kinds of sucking approximate to this last mode of taking food. 

 The Phrygance make, as it were, the passage from the mandibulate to 

 the haustellate insects, their oral organs being formed wholly upon the 

 type of the mandibulates, although they only take their food by suction. 

 Their mandibles are small, and entirely unadapted to biting, and have 

 the appearance of two little knobs at the base of the labrum (PI. VI. 

 f. 9. a, a}, whereas the upper lip, or labrum, is long, narrow, lancet- 

 shaped, internally canaliculated (the same, f. 9.), the same as the still 

 longer labium, which is distended at its extremity into a spoon-shape 

 (the same, f. 10. d.} ; with it the two-jointed, flat, lobate maxillae (the 



