74 



PROCEEDINGS OF THE AMERICAN ACADEMY 



Fig. 1. 

 B 



Fig. 2. 

 B 



cells on one side of the comb ceases to be parallel with those on the 

 other, with which it was connected when the comb was begun, and 

 diverges from them, it is gradually transferred to a new series ; as the 

 cells come in contact with those of the new series, the fourth side ap- 

 pears, and, at the same time, one of the original sides, viz. that directly 

 opposite to it, is gradually diminished, and may vanish. This di- 

 vergence is, however, sometimes insufficient to make the separation 

 of the rows complete, and may gradually diminish again, as they are 

 extended by the construction of new cells, so as to bring them back 

 to the original position, when the irregularity is corrected. 



If, however, the separation of the two rows at length becomes com- 

 plete, so that one of the faces is lost and a new one formed, all the basal 

 portion of the cell becomes reversed, as will be seen by reference to 



Figs. 1 and 2 ; the first rep- 

 resenting the cells when the 

 base is viewed, and the 

 second when looked at per- 

 pendicularly to one of the 

 sides. In both figures A 

 indicates the ordinary form 

 of the cell. The whole se- 

 ries of Fig. 1 shows the 

 gradual introduction of the 

 new face, which is seen on 

 the lower border, and the 

 elimination of one of the original faces, which is seen on the upper 

 border. At B, which is intermediate between the two extremes, the 

 four faces consist of two equal rhombs, — one of which is the outgoing 

 and the other the incoming one, — and two equal hexagons. B, Fig. 2, 

 represents the sides of the same cell, which, instead of forming three 

 trapeziums, as at A, a, b, c, now form two pentagons, a' and c', and a 

 parallelogram, b'. At C, Figs. 1 and 2, the forms are in all respects 

 the reverse of those of A. A and C are symmetrical with each other, 

 and B is symmetrical in itself. No precise number of cells is neces- 

 sary for the purpose of making this transition, for it may take place in 

 two or three, or extend through a long series, as in Fig. 1. 



There is another variation which we have noticed twice, — once in 

 drone, and once in worker comb, involving a large number of cells. If 

 a piece of normal comb be held in the position in which it was built, 



of i' V 



