CiiAP. VII. rELL-MAKINO INSTLXCT. 223 



tain circumsluuccs a rough wall in its proper place l>elwccn two 

 just-commenced cells, is important, as it bears on a fact, which 

 seems at first quite subversive of the foregoing theory ; namely, 

 that the cells on the extreme margin of Avasp-combs are some- 

 times strictly hexagonal ; but I have not space here to enter 

 on this subject Nor does there seem to me any great difii- 

 culty in a single insect (as in the case of a queen-wasp) making 

 hexagonal cells, if she were to work alternately on the inside 

 and outside of two or three cells commenced at the same time, 

 always standing at the proper relative distance from the parts 

 of the cells just Ix^guji, sweeping spheres or cylinders, and 

 building up intermediate planes. 



As natural selection acts only by the accumulation of slight 

 modificiitions of structure or instinct, each profitable to the 

 individual under its conditions of life, it may reasonably be 

 asked, how a long and graduated succession of motlified archi- 

 tectural instincts, all tending toward the prcsent perfect plan 

 of construction, could have profited the progenitoi-s of the hive- 

 bee ? I think the answer is not diflicult: cells constructed 

 like those of the bee or the wasp gain in strength, and save 

 much in labor and space, and in the materials of which they 

 are constructed. With respect to the formation of wax, it is 

 known that bees are often hard pressed to get sufficient nectar, 

 and I am informed by Mr. Tegetmeier that it has been experi- 

 mentally proved that from twelve to fifteen poimds of dry 

 sugar arc consumed by a liive of bees for the secretion of each 

 pound of wax; so that a prodigious quantity of fluid nectar 

 nmst be collected and consumed by the bees in a hive for the 

 secretion of the wax necessary for the construction of their 

 combs. Moreover, many bees have to remain idle for many 

 days during the jirocess of secretion. A large store of honey 

 is indispensable to support a largt; stock of bees during the 

 winter ; and the security of the hive is known mainly to depend 

 on a large number of bees being supported. Hence the saving 

 of wax by largely saving honey and the time consumed in col- 

 lecting the honey must be an important element of success to 

 any family of bees. Of course, the success of the species ma\- 

 be dependent on the number of its enemies, or parasites, or on 

 (juite distinct caiuses, and so be altogether independent of the 

 quantity of honey which the bees could collect. But let us 

 suppose that this latter circumstance determined, as it proba- 

 bly often has determined, whether a bee allied to our liumble- 

 bces could exist in large nuinbere in any country ; and let us 



