INSECTS. 481 



been removed for the purpose of viewing the several parts, 

 which consist of two spongy palpi, or feelers, covered 

 with short hairs, and united to the head by a set of muscles ; 

 these feelers appear to be in frequent requisition 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 enclosed 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 retractile character of which may be seen in the 

 drawing of the proboscis of the Fly, fig. 242 : by the aid of 

 two booklets placed in each side, he is enabled to draw 

 in and dart out the tongue with wonderful rapidity. The 

 striated appearance of another set of muscles is seen at 

 the root of the whole. 



" In the organisation of the mouth of various insects 

 we have a modification of form, to adapt them to a dif- 

 ferent 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 ap- 

 pears 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 expanded, to encompass the wound made by 

 the insect with its lancet-shaped mandibles in the skin of 

 I i 



