238 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 



from 9 to 18 days, and the minute larvae immediately hunt for the 

 fruit. Those finding it bore in at once and spend from 10 to 30 

 days feeding upon the seeds and flesh around the core. At maturity 

 the larvae emerge, chiefly at night, and seek sheltered places, such as 

 holes or cracks in the trees or ground, crevices under bark scales on 

 the trunk, or refuges under boards or other litter on the ground in 

 which to spin their cocoons. (PL X, figs. 2 and 3.) Here they either 

 pupate at once in preparation for the second brood of the season, or, 

 if winter is near, pupation is postponed till the following spring. 

 The adults fly mostly by night. 



DESTRUCTION OF LARV^ BY BIRDS. 



Thus the nocturnal habits of the species in its active stages and 

 the fact that it is hidden at other times leave few opportunities for 

 birds to attack it. In spite of this, however, birds destroy great 

 numbers. Some larvae are no doubt captured during the interval 

 between emergence from the fruit and spinning the cocoon, but as 

 this period is brief and usually occurs at night, a great majority of 

 them probably reach a hiding place in safety. But woodpeckers 

 drill through the bark flakes under which larvae or pupae lie in 

 their cocoons, or enlarge cracks that shelter large numbers of these 

 insects in immature stages, and the titmice, chickadees, nuthatches, 

 and creepers find them in shallow crevices or by prying off loose 

 scales of bark. Probably most of the other birds, also, which feed 

 upon the larvae and pupae get them chiefly by these latter methods. 



WOODPECKERS. 



The most effective enemies of codling moths are those that can 

 best attack them in their pupal chambers. It is not surprising, 

 therefore, that woodpeckers, accustomed as they are to obtaining 

 their food from crevices and under bark flakes, should take high 

 rank among the foes of this pest. (PI. XI.) 



Roesel, the first man who published an accurate account of the 

 codling moth, noted the beneficial work of woodpeckers. He says 

 of the larvae seeking places to pupate : " They conceal themselves so 

 thoroughly as scarcely to be found by men ; but the woodpeckers and 

 similar birds know how to discover quickly their retreats." 1 



Trimble, an American investigator, was the first to -ascertain how 

 the downy woodpecker " finds where to peck through the scales of 

 bark, so as to be sure to hit the apple worm that is so snugly con- 

 cealed beneath." After stating that the sense of smell will not ac- 

 count for it, he says : 



1 Roesel von Rosenhof, A. J. Insecten-Belustigen : l ter Theil, Der Nachtvogel, 4 te 

 Classe, No. 13, p. 36, 1746. 



