STRUCTURE OF INSECTS. W 



is immediately under the root of the claw, has two 

 suckers appended to it by a narrow, funnel-shaped neck, 

 Fig. 54. moveable by muscles in all direc- 



tions. These suckers are shown in 

 Fig. 54, which represents the under 

 side of the foot of the blue bottle 

 Fly, (Musca vo??iitoria,) 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 Horse Fly each foot is furnished with three suckers. 



Mechanism in the Saw Fly. In the yellow Saw Fly, 

 (Cimbex lutea,) there are four suckers, of which one is 

 placed upon the under surface of each of the first joints 



of the toes, Fig. 55. All the feet of this insect are thus 

 provided. Both of these figures are highly magnified. 



The mode in which these suckers operate may be 

 distinctly seen, by observing with a magnifying glass, 

 the actions of a large blue bottle Fly in the inside of a 

 glass tumbler. A Fly, by the application of this appa- 

 ratus will remain suspended from the ceiling with his 

 back downwards, for any length of time, without the 

 least exertion ; for the weight of the body pulling 

 against the suckers, serves to make them adhere strong- 

 er, for the same reason that a boy's leather sucker ad- 

 heres more forcibly in lifting a large stone, than a small 

 one. For this reason it is, that house Flies prefer the 

 ceiling to an upper surface, as a place of rest. 



In what manner is it said the house fly adheres to the under surfaces 

 of smooth bodies 1 



