28 NEW YORK STATE MUSEUM 



sene emulsion or some similar preparation, thousands of these 

 insects can be killed. As it requires six or seven days for the 

 larvae to pass through the pupal stage to beetles, thi& 

 operation need not be performed oftener than once in five days 

 to insure the destruction of all that have pupated within reach 

 of such a measure. The nearly simultaneous descent of the 

 grubs is very favorable to this way of checking the insect and 

 reduces the necessary labor to a minimum. To make this 

 method more effective, it has been recommended to inclose 

 a limited smooth area around each infested tree, preferably 

 cemented, boards being arranged to prevent the larvae from 

 escaping to shelters where they could less easily be destroyed. 

 Such an inclosure might be advisable around small trees with 

 relatively smooth bark and no overhanging limbs, but it would 

 hardly pay to treat larger trees thus on account of the large 

 number of larvae pupating in the crevices of the bark or drop- 

 ping from the tips of overhanging limbs. The great objection 

 to fighting the insect at this stage is that the injury has already 

 been accomplished, but to do even this is much better than to 

 allow it to go on unchecked, because it must have some influence 

 on the future abundance of the beetle. The destruction of 

 larvae and pupae around the base of the trunk may well be 

 undertaken to supplement the spraying and thus secure the 

 destruction of the largest possible number of the insects. 



USELESS MEASURES 



Though the life history of this beetle is well known, at least 

 to entomologists, it is surprising how people will cling to some 

 false idea, gained they know not where, of the method of fight- 

 ing this or some other insect. One of the most persistent of 

 these fallacies is that cotton placed around the trunk will pro- 

 tect a tree from the elm leaf beetle. Under certain conditions 

 a band of cotton, tar or other substance will protect trees from 

 some insects, but never from the elm leaf beetle. It should be 

 understood that the parent insect flies up into the tree, feeds 

 for a time and then lays the eggs from which the grubs emerge 

 to commence their injurious work. The band can not have the 



