Vol 'i9i9 XVI ] Recent Literature. 305 



Larch bark-beetles and borers.— In a general account of insects affect- 

 ing the larch in Erie County, N. Y., is the following interesting infor- 

 mation, relating to the work of woodpeckers. 1 



" The work of woodpeckers is much in evidence and seems to be an effi- 

 cient agency in reducing to some extent the numbers of the brood of several 

 of the more numerous bark-boring insects. The birds seem to work in two 

 ways — first by making small conical holes through the bark into the sap- 

 wood to obtain the larvae of the larger species of beetles which have gone 

 there to hibernate or to pupate, and secondly by removing practically all 

 of the bark on large areas of the trunk to uncover the brood (larvae, pupae 

 and young adults) of the bark beetles. 



" In some cases this work reached an unusual degree of efficiency. For 

 instance one particular tree forty or fifty feet high and about 14 inches in 

 diameter, had had nearly all of the bark removed from the ground to the 

 very tip. This tree had been heavily infested with Dendroclonus simplex, 

 Polygraphia rufipennis and other borers, but only a small per cent of the 

 original infestation had survived the woodpeckers' thorough search for 

 food. Of course all of the infested trees had not been so thoroughly gone 

 over by the birds and a number of such trees had apparently not been found 

 by them at all. However, it is safe to say that the woodpeckers were an 

 efficient force, working toward the return of the normal balance of nature 

 which had been upset by the breeding of certain species of insects above the 

 danger level, due to the girdling, season after season, of a number of the 

 larches by farmers. It is not believed that the woodpeckers will be able 

 unaided to reduce the numbers below the danger level, as long as more 

 trees are girdled each year, but should this practice cease it is possible that 

 they would be able eventually to obtain the upper hand and that conditions 

 would return to normal." 



Lepidopterous root-borers. — The grape root-borer (Memythrus poli- 

 stiformis) for which no parasites are known was seen to be eaten in the 

 adult stage by the Crested Flycatcher (Myiarchus crinitus). 2 Two 

 other Flycatchers, the Kingbird and Phoebe, are recorded as enemies of 

 both the greater and lesser peach-tree borers (Sannenoidea exitiosa and 

 Synanthedon pictipes). 3 All of these insects are not only seriously destruc- 

 tive, but from their secluded habits in the larval stage, have few parasite 

 enemies and are difficult to control by man. They belong to a family 

 of moths all of which in the adult condition more or less closely mimic wasps 

 and other hymenoptera and which have been supposed, probably mis- 

 takenly, to derive some advantage from this resemblance, in the way of 

 immunity from predatory enemies. 



Cankerworms. — An investigation of the relation of birds to canker- 



» Blackman, M. W. and Stage, Harry H. Tech. Publ. No 10, N. Y. State College of 

 Forestry, May, 1918, pp. 16-17. 



* Brooks, L. E. BjII. 730, U. S. Dept. Agr., Dec. 24, 1918, p. 27. 



• Gossard, H. A. and King, J. L , Bull. 329, Ohio Agr. Exp. Sta. Sept., 1918, p. 70 



