Packard.] THE SOCIAL LIFE OF INSECTS. 339 



downwards. I have noticed in Virginia during the last week 

 in April three species of Polistes beginning their nests, and 

 working in the same manner. I never saw the nests at an 

 earlier stage than when consisting of three cells, but it was 

 easy to see tliat the first cell was only partially built before 

 the other two were begun, and that virtually the wasp 

 builds the three cells almost simultaneously. Tlie outer 

 edges of the incipient cells are said by Waterhouse to be 

 perfectly circular, but at the time I saw them they were 

 slightly angular on the outer edge, and by the time the cells 

 are nearl}- completed the hexagonal form of the cells is 

 attained. The wasp thus changes her plan of working, be- 

 ginning to build them saucer-shaped, then cup-shaped, and 

 finally- forming them into deep hexagonal tubes. But one 

 wasp, a female which has hibernated, builds a cell. Now 

 this act of building the six-sided cell is in the wasps of the 

 present day purely instinctive, but I firml_y believe that when 

 nature had the ancestors of these wasps in training, the}^ 

 built rude, solitary, more or less si)lierical cells, and only as 

 the force of surrounding circumstances made them social, 

 did they build more than one cell and put them together, 

 w^hen they were obliged partly by the necessity of mathe- 

 matical laws, acting in a degree under the control of their 

 reason, to build them in hexagons. There are social bees, 

 such as the humble bees, in which the cells made by the 

 larvie are oval, though closely pressed together. Wh}'^ do 

 not they assume a hexagonal form if this is due simply to 

 mechanical pressure? But look at the adult honey ])ee, or 

 the ]Melii)ona or Trigona, wliich build hexagonal cells. They 

 are not wholly the instruments of mechanical laws, but prob- 

 ably had in the earlier histor}' of the species sulllcient intel- 

 lect to enable them to build their cells in hexagons. I am 

 induced to take this view from seeing the wasp change its 

 plan of building from a circular to a hexagonal one, as the 

 cells grow higher and become more numerous. These crea- 



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