62 NEW YORK STATE MUSEUM 



that this period is more nearly the normal time between 

 the emergence of the beetles and feeding. A considerable num- 

 ber may be found before any feeding has taken place, as is evi- 

 denced by Mr Barden taking 12 from a vine which bore prac- 

 tically no marks of their eating. The insects may be found in 

 a field over an extended period. Some were observed by Mr 

 T. T. Neill Sep. 4, 1902, in a vineyard at Fredonia. 



Oviposition does not occur till some days after the appear- 

 ance of the perfect insects and according to breeding cage 

 observations this period may range from 10 to 17 days. Our 

 breeding cage experiments also indicate that the insect may 

 feed from 6 to 13 days before eggs are deposited. This period 

 was carefully ascertained by isolating a series of males and 

 females and' providing them with as nearly natural conditions 

 •as poiSisible. Both of these periods are much longer than nor- 

 mal, since eggs were found by Mr Barden in the Northrop vine- 

 yard July 9, where beetles were present in very small numbers 

 on the second. This allows a maximum of only seven days 

 between the appearance of the earliest insects and the deposi- 

 tion of eggs, and, if, as can hardly be questioned, the insects 

 remain without taking food for two or three days, then the 

 time of feeding before the deposition of eggs can hardly exceed 

 an equal period. This matter is of considerable importance 

 because it shows how quickly poisons must act in order to 

 prevent the deposition of any eggs. 



The feeding of the beetles occurs almost entirely on the upper 

 surface of the leaves and, as described by Professor Webster, 

 ^' is done by gathering a quantity of the substance of the leaf in 

 the mandibles and jerking the head upwards, after which the 

 body is moved a step forward and another mouthful of food 

 secured as before. After securing a few mouthfuls in this way 

 they move to another place and begin again, thus eating out 

 numerous chainlike rows of silk net as shown on plates 5 and 1, 

 figure 2. The insects eat only to the lower epidermis on foliage 

 having a velvety under surface, but on others they eat entirely 

 through the leaf." The individuals feeding on the leaves are 



