INSTINCT 225 



placed in two parallel layers; with the centre of each sphere at 

 the distance of radius X V 2, or radius X 1,41421 (or at some 

 lesser distance), from the centres of the six surrounding spheres 

 in the same layer; and at the same distance from the centres of 

 the adjoining spheres in the other and parallel layer; then, if 

 planes of intersection between the several spheres in both layers 

 be formed, there will result a double layer of hexagonal prisms 

 united together by pyramidal bases formed of three rhombs; and 

 the rhombs and the sides of the hexagonal prisms will have every 

 angle identically the same with the best measurements which have 

 been made of the cells of the hive-bee. But I hear from Pro- 

 fessor Wyman, who has made numerous careful measurements, 

 that the accuracy of the workmanship of the bee has been greatly 

 exaggerated; so much so, that whatever the typical form of the 

 cell may be, it is rarely, if ever, realized. 



Hence we may safely conclude that, if we could slightly modify 

 the instincts already possessed by the Melipona, and in them- 

 selves not very wonderful, this bee would make a structure as 

 wonderfully perfect as that of the hive-bee. We must suppose 

 the Melipona to have the power of forming her cells truly spher- 

 ical, and of equal sizes; and this would not be very surprising, 

 seeing that she already does so to a certain extent, and seeing 

 what perfectly cylindrical burrows many insects make in wood, 

 apparently by turning round on a fixed point. We must suppose 

 the Melipona to arrange her cells in level layers, as she already 

 does her cylindrical cells; and we must further suppose, and this 

 is the greatest difficulty, that she can somehow judge accurately 

 at what distance to stand from her fellow-laborers when several 

 are making their spheres; but she is already so far enabled to 

 judge of distance, that she always describes her spheres so as to 

 intersect to a certain extent ; and then she unites the points of in- 

 tersection by perfectly flat surfaces. By such modifications of in- 

 stincts which in themselves are not very wonderful — hardly more 

 wonderful than those which guide a bird to make its nest — I be- 

 lieve that the hive-bee has acquired, through natural selection, 

 her inimitable architectural powers. 



But this theory can be tested by experiment. Following the ex- 

 ample of Mr. Tegetmeier, I separated two combs, and put be- 

 tween them a long, thick, rectangular strip of wax: the bees 

 instantly began to excavate minute circular pits in it ; and as they 

 deepened these little pits, they made them wider and wider until 

 they were converted into shallow basins, appearing to the eye 

 perfectly true or parts of a sphere, and of about the diameter of 



