APIAKI^. 121 



proposed what has been called the ''circular theor}-," or what 

 the author himself terms "the principle of working in seg- 

 ments of circles." He contends " that the hexagonal form of the 

 cells of certain bees and wasps may, and does, arise out of this 

 mode of action when under certain conditions ; that those condi- 

 tions are, that the cells are so commenced that their natural cir- 

 cumferences, as the work proceeds, are either simpl}- brought 

 into contact with each other, or that the cells are so placed that 

 the (we will say theoretical) circumferences must intersect. 

 Contact with adjoining cells, then, is an essential condition to 

 bring about the hexagonal form as I have before pointed out 

 (See Proceedings of the Entomological Society, 1858, p. 17) ; 

 but for this result it is not necessary that a hexagonal cell 

 should be completely surrounded by other cells." 



Is not this theor}', after all, too mechanical? Is not our bee 

 more of a free agent? Does it not have a mind to design its 

 work? Mr. F. Smith, Avho has devoted years to the study of 

 Hymenoptera, especially the higher forms of this suborder, the 

 Bees and AVasps, replies to both theories of AVaterhouse and 

 Haughton, by bringing in the case of the AVasps which also 

 build hexagonal cells, showing that a solitary wasp will build 

 its cells in ver^^ regular hexagons. Thus the nest of the soli- 

 tary AA^asp, Icaria guttatipennis, " consists of a double row, the 

 number of cells being ten ; I now direct your attention to the 

 fact that all the cells are perfectly hexagonal, the exterior 

 planes being as beautifully finished as tliose in contact with 

 the inner planes of the opposing cells. I have placed a draw- 

 ing of this nest (Plate 5, Fig. 7) in the box on the table, and I 

 particularly wish you to observe, that the first cell is carried 

 up in a i)erfectly hexagonal form above the adjoining cells ; a 

 pro(^f that, if AVasps never build perfect isolated hexagonal cells, 

 they certainl}^ possess the capability of doing so. The exterior 

 of all the cells, as I before observed, is hexagonal, not cylindri- 

 cal, until fresh cells are added on the outer side, as was ob- 

 served to be the case in combs of the Hive-bee, by Mr. 

 Tegetmeier." (Proceedings of the Entomological Society of 

 London. Third series, ii, 1864, p. 135.) 



An examination of the cells of three species of PoJistes (the 

 female of which begins alone in the spring to build her nest 



