244 SPECIAL INSTINCTS. 



stincts you please, it seems at first quite inconceivable how 

 they can make all the necessary angles and planes, or even 

 perceive when they are correctly made. But the difficulty 

 is not nearly so great as at first appears : all this beautiful 

 work can be shown, I think, to follow from a few simple 

 instincts. 



I was led to investigate this subject by Mr. Waterhouse, 

 who has shown that the form of the cell stands in close 

 relation to the presence of adjoining cells ; and the following 

 view may, perhaps, be considered only as a modification of 

 his theory. Let us look to the great principle of gradation, 

 and see whether Nature does not reveal to us her method of 

 work. At one end of a short series we have humble-bees, 

 which use their old cocoons to hold honey, sometimes 

 adding to them short tubes of wax, and likewise making 

 separate and very irregular rounded cells of wax. At the 

 other end of the series we have the cells of the hive-bee, 

 placed in a double layer: each cell, as is well known, is 

 an hexagonal prism, with the basal edges of its six sides 

 bevelled so as to join an inverted pyramid, of three rhombs. 

 These rhombs have certain angles, and the three which 

 form the pyramidal base of a single cell on one side of the 

 comb enter into the composition of the bases of three ad- 

 joining cells on the opposite side. In the series between 

 the extreme perfection of the cells of the hive-bee and the 

 simplicity of those of the humble-bee we have the cells of 

 the Mexican Melipona domestica, carefully described and 

 figured by Pierre Huber. The Melipona itself is interme- 

 diate in structure between the hive and humble bee, but 

 more nearly related to the latter ; it forms a nearly regular 

 waxen comb of cylindrical cells, in which the young are 

 hatched, and, in addition, some large cells of wax for hold- 

 . ing honey. These latter cells are nearly spherical and of 

 nearly equal sizes, and are aggregated into an irregular 

 mass. But the important point to notice is, that these 

 cells are always made at that degree of nearness to each 

 other that they w r ould have intersected or broken into each 

 other if the spheres had been completed ; but this is never 

 permitted, the bees building perfectly flat walls of wax be. 

 tween the spheres which thus tend to intersect. Hence, 

 each cell consists of an outer spherical portion, and of two, 

 three, or more flat surfaces, according as the cell adjoins 

 two, three, or more other cells. When one cell rests on 

 three other cells, which, from the spheres being nearly of 



