STRUCTURE OF INSECTS. 



•297 



Some insects are furnished with a still more 

 refined and effectual apparatus for adhesion, and 

 one which even enables them to suspend them- 

 selves in an inverted position from the under 

 surfaces of bodies. It consists of suckers, the 

 arrangement and construction of which are exceed- 

 ingly beautiful ; and of which the common house- 

 fly presents us with an example. In this insect 

 that part of the last joint of the tarsus which is 

 immediately under the root of the claw, has two 

 suckers appended to it by a narrow funnel-shaped 

 neck, moveable by muscles in all directions. These 

 suckers are shown in Fig. 152, which represents 

 the under side of the foot of the 3Iusca vomitoria, 

 or blue-bottle fly, with the suckers expanded. 

 The sucking part of the apparatus consists of a 

 membrane, capable of contraction and extension, 

 and the edges of which are serrated, so as to fit 

 them for the closest application to any kind of 



surface. In the Tabaniis, or horse-fly, each foot is 

 furnished with three suckers. In the Cimbex lutea, 

 or yellow saw-fly, there are four, of which one is 

 placed on the under surface of each of the four 



the Dynastidce, which are among the largest of the Coleoptera, 

 have no such cushions : while the small Longicornua are provided 

 with them. In the Harpalidce, which do not fly, cushions exist only 

 in the male insects. 



