INSECTS: THEIR FEET 145 



is connected with the feeding of the stock, and whatever 

 diminishes the labor of the individual bees enables a larger 

 number to be supported. But valuable as is the Honey- 

 bee to man, there are other important purposes to be ac- 

 complished, which are more or less dependent, collaterally, 

 on this series of contrivances. 



"In many instances it is only by the bees travelling 

 from flower to flower that the pollen and farina is carried 

 from the male to the female flowers, without which they 

 could not fructify. One species of bee would not be suffi- 

 cient to fructify all the various sorts of flowers were the 

 bees of that species ever so numerous; for it requires spe- 

 cies of different sizes and different constructions. M. 

 Sprengel found that not only are insects indispensable in 

 fructifying different species of Iris, but some of them, as 

 /. Xiphium, require the agency of the larger humble-bees, 

 which alone are strong enough to force their way beneath 

 the style-flag; and hence, as these insects are not so com- 

 mon as many others, this Iris is often barren, or bears 

 imperfect seeds. ' ' ' 



The legs and feet of Caterpillars are constructed on a 

 very different plan from those of perfect insects, as you 

 may see in this living Silkworm. The first three segments 

 of the body, reckoning from the head, are furnished each 

 with a pair of short curved limbs set close together on the 

 under side. These represent the true legs of the future 

 rnoth, and show, notwithstanding their shortness, four dis- 

 tinct joints, of which the last is a little pointed horny 

 claw. The whole limb resembles a short stout hook. The 

 two segments occur which are quite smooth beneath, and 



1 "Penny Cyclop.," art. BEE. 

 15 SCIENCE 7 



