250 SPECIAL INSTINCTS. 



spheres ; but as far as I have seen, they never gnaw away 

 and finish off the angles of a cell till a large part both of 

 that cell and of the adjoining cells has been built. This 

 capacity in bees of laying down under certain circumstances 

 a rough wall in its proper place between two just commenced 

 cells, is important, as it bears on a fact, which seems at first 

 subversive of the foregoing theory ; namely, that the cells 

 on the extreme margin of wasp-combs are sometimes strictly 

 hexagonal ; but I have not space here to enter on this sub- 

 ject. Nor does there seem to me any great difficulty in a 

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

 agonal 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 begun, sweeping spheres or cylin- 

 ders, and building up intermediate planes. 



As natural selection acts only by the accumulation of 

 slight modifications of structure or instinct, each profitable 

 to the individual under its conditions of life, it may reason- 

 ably be asked, how a long and graduated succession of modi- 

 fied architectural instincts, all tending toward the present 

 perfect plan of construction, could have profited the pro- 

 genitors of the hive-bee ? I think the answer is not difficult : 

 cells constructed like those of the bee or the wasp gain in 

 strength, and save much in labor and space, and in the mate- 

 rials 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 experimentally proved that from 

 twelve to fifteen pounds of dry sugar are consumed by a hive 

 of bees for the secretion of a pound of wax ; so that a pro- 

 digious quantity of fluid nectar must be collected and con- 

 sumed 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 

 process of secretion. A large store of honey is indispensa- 

 ble to support a large 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 

 may be dependent on the number of its enemies, or para- 

 sites, or on quite distinct causes, and so be altogether inde- 



