48 



THE GEAPE ROOT-WORM. 



these cages varied from 1 to 2^ inches, and were of a uniform height of 

 20 inches. The two larger sides consisted of plate glass with outer 

 wooden shutters on either side which could be removed for the exami- 

 nation of the contents. 



The emergence records of Table I, as shown by curve in figure 

 13, are the results of about 15 separate experiments with larvse 

 transforming in large earthen pots filled with soil. Since the time 

 of emergence of the beetles and their relative occurrence has a 



direct bearing upon the 

 time of application of poison 

 sprays against this pest, 

 special attention and care 

 were exercised in preparing 

 these experiments. In the 

 early spring approximately 

 1,000 larvae were collected 

 in different vineyards in the 

 vicinity of North East, Pa. 

 In many instances soil from 

 different localities, which 

 varied from loose sandy soils 

 to heavy clay, was trans- 

 ferred with the larvae to the 

 rearing pots (fig. 22). Pro- 

 vision for the spring feeding 

 of the larvae was made by 

 planting young grapevines 

 in the pots. Finally the 

 pots were placed in the 

 ground in the open field and 

 were left undisturbed for the 

 rest of the season. Before 

 the beetles commenced to 



Fig. 22.— Earth en pot with wire-screen cover used in rear- appear wirC SCTCen COVCrS 

 ing the grape root- worm. (Original.) ^^^^ placed OVCr Cach pot, 



SO that a complete daily record could be kept of the number of 

 beetles emerging from each separate pot. 



By preserving the beetles from the above-mentioned experiments, 

 rearing material of known source and age was obtained for further 

 experiments. The daily catch of beetles throughout the emergence 

 period was transferred to so-called ''stock jars," from which insects 

 were taken as needed for miscellaneous experiments. The "stock 

 jars" shown in the rearing shelter (fig. 18) consisted of large-sized 

 glass jars covered with thin cloth. A layer of moist sand was placed 



