PROCEEDINGS OF THE ANNUAL MEETING. 341 



usually recommended, just after the blossoms fall, has been fully demon- 

 strated over and over again by almost every experiment station in the 

 country and by many of our leading horticulturists. But it will be found 

 that the explanations as to just how the poison kills the worm are obscure^ 

 indefinite, and vary considerably. The reason for this seems to be that 

 no one has apparently made any careful and definite observations on the 

 eggs and newly-hatched caterpillars. The usually accepted statement, 

 as taken from our leading text-book on entomology, is: '' The moth lays 

 its eggs singly in the maturing blossom of the apple just as the petals 

 fall. So soon as the caterpillar hatches it burrows into the apple." 

 Almost everyone who writes about the insect glibly tells when and where 

 the egg is laid, but so far as my search through the literature has yet 

 extended, I have found only one instance where the writer had evidently 

 ever seen the egg. This statement seems all the more remarkable when 

 we realize that the literature of the pest dates back to as early as 1728, 

 and is probably as voluminous as that of any other injurious insect. The 

 only definite account of the egg-laying habits of the codlin moth, based 

 upon actual observations, I have been able to find, were published in 189)^ 

 in Bulletin No. 25, issued from the Oregon experiment station. I believe 

 this bulletin contains the first and only picture of the egg yet published. 

 The" author, Mr. Washburn, found that the eggs were laid anywhere it 

 happened, on the skin of the fruit, and consequently later than was sup- 

 posed; these important observations seem to have been overlooked by 

 later writers. Unfortunately the operations of the young caterpillar after 

 it emerges from the egg were not observed by Mr. Washburn, thus leaving 

 it still uncertain just how it gets its deadly dose of Paris green. 



My observations and experiments indicate that most of the eggs are not 

 laid until about a week after the blossoms have fallen, when the apples 

 are about the size of hickory nuts. At this time the calyx lobes on the 

 young apples are drawn tightly together, so that it would be difiicult for 

 the moth to insert her egg in the calyx cup; in fact, the hoof-like oviposi- 

 tor of the female is only adapted to laying her eggs on the surface of the 

 fruit. The nearly round, very thin, scale-like, semi-transparent eggs, not 

 quite so large as the head of a common pin, are glued to the skin of the 

 apple, with apparently but little choice as to its location on the fruit. 

 As it takes about a week for the eggs to hatch, it is thus from ten days 

 to two weeks after the blossoms fall before the caterpillars begin oper- 

 ations. If the usual recommendations for spraying have been followed, 

 the first application of Paris green is made a week before the eggs are 

 laid, and the second application several days before the worms begin 

 work. With these facts before us, we were at a loss to explain just how 

 the poison could kill the worm. However, a study of the developing 

 fruits of many different varieties of apple disclosed the following facts: 

 When the petals of the blossoms fall, the calyx lobes which remain are 

 broadly spread out, saucer-like, and many minute particles of Paris green 

 could be, and in fact are, readily caught in the calyx cup. But, as about 

 two weeks must intervene before the little caterpillar begins eating, 

 much of this poison would ordinarily be washed out by the rains, and the 

 first spraying thus be useless. However, nature prevents this by simply 

 causing the calyx lobes to be drawn tightly together at their tips, as the 

 apple grows, so that usually within a week after the blossoms fall the 



