21 [441] 



branches, and therefore do not reach the traps. One of the trees 

 experimented with was of this kind, being upwards of fortj' years 

 old. In the summer of 1872 this tree was tolerably well filled with 

 apples, the greater part of which fell to the ground in consequence of 

 the injuries of the Codling- worms, and were allowed to remain there for 

 the sake of experiment. Upon the trunk of this tree were put, early in 

 the season, tw o of Wier's traps and a carpet band. These appliances 

 were examined for the first time on the 26th of July, and then only thir- 

 ty larvae and pupte were found in all of them ; whilst from two other 

 trees, not half as large, I obtained 129 and 260 worms, respectively. 

 The only exx)lanatiou I could give of this remarkable dilierence was that 

 a large proportion of the worms had left the apples before they fell, and 

 found shelter beneath the scales of bark on the limbs of this rough old 

 tree. To determine this point I spent a couple of hours in picking off 

 the scales on the large branches, and in this time discovered thirty 

 worms or pupte, the same number that had entered the traps, and yet 

 I examined onlj- a very small part of the tree's surface. 



AID TO BE EXPECTED FROM NATURAL ENEIVHES. 



Those injurious insects which inhabit the substance of our fruits, 

 such as the plum-curculio, the plum-gouger, and the codling-worm, 

 escax^e in this way, to a great degree, the attacks of natural enemies, 

 whether birds, or predaceous or parasitic insects — enemies to which 

 the soft, naked, pinkish- white bodies of the codling-worm would other- 

 wise offer a very temptmg bait. The only time in their lives when they 

 are exposed to view is the brief period after leaving the apple, and 

 whilst seeking for a covert in which to spin their cocoons, and there is 

 good reason for belie\ing that they usually take advantage of the dark- 

 ness of night for this purpose. In this way they must escape, to a 

 great exient, the many kinds of small insectivorous birds, all of which 

 are diurnal. Their only eflQcient enemies amongst the birds are the 

 woodpeckers, whose instinct enables them to discover and devour them 

 in their winter retreats. The boards of apple bins in open out-houses 

 often bear unmistakable marks of the penetrating beaks of these busy 

 insect-hunters, and I have seen the shingles of which Mr. Wier's traps 

 were made, and which had been left on the trees through the winter, 

 ruined for future use by being riddled with holes made by woodpeckers 

 in digging out the worms concealed between the layers. The same in- 

 stinct enables them to discover the worms in their natural retreats be- 

 neath the bark, and many of the insects are known to be destroyed in this 

 way ; and it is an encouraging circumstance that the worms which es- 

 cape our traps by pupating upon the branches, are exposed to the per- 

 tinacious search of the woodpeckers all through the autumnal, winter 



