SEASONAL HISTORY. 



49 



in each jar, which made it easier for the insects to move about and 

 made the conditions more natural. Grape fohage, constituting the 

 food of the beetles, was supplied daily, and to prevent unhealthy con- 

 ditions in the cages the old leaves were always removed. For ovi- 

 position short pieces of grapevine cane were placed with the beetles, 

 and as egg depositions progressed these canes were removed daily 

 and replaced by fresh ones. In determining the number of eggs 

 deposited, the loose bark had to be peeled off the pieces of cane and 

 the eggs in each cluster carefully counted. In determining the egg 

 deposition of individual females and the length of life of male and 

 female beetles, pairs when found in copulation in the stock jars were 



AiAY 



5 10 15 to 95 



JUNE 



S '0 15 20 ZS 



JULY 



5 10 /5 ZO 2S 



AUG. 



5 '0 15 20 iS 



5£Pr. 



5 /O /5 20 2S 



OCT. 



5 /o 15 50 9.5 



N0\/. 



5 10 /5 20 3S 





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er c 



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TTrrrr 





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II 



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11 



Fig. 23.— Diagram illustrating seasonal history of the grape root-worm as observed during 1909 at 



North East, Pa. (Original.) 



isolated previous to the earliest egg deposition. The observations on 

 the habits of these individual beetles are given in Table II. 



Since the greater portion of the beetles from the emergence cages 

 was used in obtaining the egg records, and since these insects ovi- 

 posited undisturbed during the entire season, it is believed that the 

 records in figure 15 represent the relative occurrence of eggs in the 

 field. 



Eggs used in determining the length of time of incubation were 

 kept in glass tumblers under the outdoor breeding shelter. 



In conjunction with the rearing work, field observations were con- 

 stantly made, and in certain* instances collections of the insect in its 

 different stages were regularly made in the same localities for a giyen 

 length of time. Thus it has been possible to check the rearing obser- 

 51282°— Bull. 89—10 4 



