insects' tongues. 593 



been removed for the purpose of bringing the several parts 

 into view, and which consist of two palpi, or feelers, 

 covered with short hairs, and united to the head by a set 

 of muscles ; these feelers appear to be in frequent requisi- 

 tion for guarding the other organs from external injury. 

 The two lancets seen above them are formed somewhat like 

 a cutlass, or the dissecting knife of the anatomist, and are 

 purposely intended for making a deep and sharp cut, also 

 for cutting vertically with a sweeping stroke. The other 

 and larger cutting instrument appears to be intended to 

 enlarge the wound, if necessary ; or it may be for the 

 purpose of irritating and exciting the part around, thereby 

 increasing the flow of blood to the part, being jagged or 

 toothed at the extremity. The larger apparatus, with its 

 three peculiar prongs, or teeth, is tubular, to permit of the 

 blood passing through it and thence to the stomach; this 

 is inclosed in a case which entirely covers it. The spongy 

 tongue itself projects some distance beyond this apparatus, 

 and is composed of a beautiful network of soft muscular 

 spiral fibres, forming a series of absorbent tubes; and these 

 are moved by powerful muscles and ligaments, the retrac- 

 tile character of which may be seen in the drawing of the 

 proboscis of the Fly, fig. 268 : by the aid of two hooklets 

 placed in each, side, he is enabled to draw in and dart 

 out the tongue with wonderful rapidity. Another set of 

 muscles is seen at the root of the whole apparatus. 



" In the organization of the mouth of various insects we 

 have a modification of form, to adapt them to a different 

 mode of use ; as in the Muscidce, or common House-flies. 

 "When the food is easily accessible, and almost entirely 

 liquid, the parts of the mouth are soft and fleshy, and 

 simply adapted to form a sucking tube, which in a state of 

 rest is closely folded up in a deep fissure, on the under 

 surface of the head. The proboscis at its base appears to 

 be formed by the union of the lacinia above and the labium 

 below, the latter forming the chief portion of the organ, 

 which is tenanted by dilated muscular lips. In the Tabanus 

 these are exceedingly large and broad, and are widely ex- 

 panded, to encompass the wound made by the insect with 

 its lancet-shaped mandibles in the skin of the animal it 

 attacks. On their outer suriace they are fleshy and 



Q si 



