BLM LEAF BEETLE IN NEW YORK STATE 13 



tions undoubtedly had some influence on egg production and the 

 protection from unfavorable weather conditions enabled the 

 beetles to approximate the maximum quota of eggs. The record 

 is of great value since it shows clearly how long oviposition may 

 be continued by a single individual, and shows that if the adult 

 beetles can be killed by thorough spraying any time before this 

 period of greatest reproductive activity, which was about June 

 H in 1898, the deposition of a very large number of eggs can 

 be prevented, with correspondingly l^ss danger from the grubs 

 or larvae. 



The grubs emerge from the eggs early in June or about five 

 or six days after oviposition, and soon begin to feed on the 

 under surface of the leaves, producing the familiar skeletonized 

 appearance well represented on pi. 1, fig. 8 and pi. 7, flg. 1. This 

 is caused by their eating the softer under part, the upper epider- 

 mis and the veins being left. The result of their feeding is so 

 characteristic that it is easy to detect their presence by the 

 semitransparent places in partly eaten leaves and by the 

 skeletonized appearance of the foliage which has been more 

 severely attacked. 



The grubs complete their growth in 15 to 20 days in summer 

 (in cooler weather the time may be greatly extended), become 

 restless, forsake the leaves and descend the limbs and trunks 

 to a greater or less extent, seeking proper shelter for pupation. 

 In warm July weather seven days are passed in this state, in 

 September the time is extended to 12 days and in October to 24. 

 The descent of the larvae of the first brood usually occurs in 

 Albany the latter part of June; in 1896 some were observed 

 descending June 19, and beetles of the second brood were taken 

 June 30. The oviposition of the second brood of beetles begins 

 about the middle of July. From that date till late in the au- 

 tumn it is possible to find the eggs of this insect most of the 

 time in some part of the city. The beetles are naturally 

 attracted by a fresh growth of foliage and it is on the trees 

 throwing out a second or a third crop of leaves or on those not 

 attacked earlier in the season that the eggs of later generations 



