SEASONAL HISTORY. 
23 
to dig around a flat pebble, and as a result passed through 31 inches 
of soil. Another beetle left the cell July o and emerged July 6, having 
penetrated the soil for a distance of 1 inch. A third beetle left the 
cell July 16 and emerged Jul}' 19, in which time it worked through 2 
inches of soil. In the process of digging, the beetles make use of the 
mandibles and to some extent also of the legs. The cells become 
partly filled with earth by material being pushed behind and beneath 
the beetle. In this process the channel is refilled and only a small 
hole is left on the surface to indicate where the beetle emerged (PI. 
Fig. 12.— Diagram showing time and development of a single individual of the grape root-worm 
under average conditions, as observed in 1909, at North East, Pa. ^Original.) 
I, fig. 10). In vineyards where the ground remains undisturbed such 
openings can be readily found during the emergence period of the 
beetle. 
In 1909 the first beetles observed in the tield were collected by the 
senior author June 28, and, sinee daily observations were made of 
vineyard conditions, this record probably represents the earliest 
occurrence of the beetle for the season. In the breeding cages the 
