ECONOMIC ZOOLOGY- — ENTOMOLOGY. 659 



The single spring application killed 45 per cent of the scale, and did not injure 

 the trees." 



Spraying experiments in which a 10 per cent solution of kerosene emulsion 

 and Nico Sul 1 : 240 and 1 : 4S0 were used show that summer spraj-ing for the 

 pest is impracticable, due to injury to the fruit and foliage and to the extended 

 period during which the larvse are crawling. For the best results it is recom- 

 mended that standard miscible oils be employed at a strength of 1 : 15, applied 

 to the trees just as late in the spring as is possible before the buds open. 



A bibliography of 19 titles relating to the subject is appended. 



The codling moth, L. Caesar (Ontario Dept. Agr. Bui. 187, 1911, pp. 40, 

 figs. 21). — The results of a study of the life history and control of the codling 

 moth in Ontario extending over 2 shears are included in this general account. 



Observations made in 1910 of the date of pupation, length of the pupal stage, 

 and date of emergence of moths in the spring are reported in tabular form. 

 It is said that in 1910 the spring was abnormally warm in the early part and 

 very cold later on. The periods passed in the pupal stage varied from 57 days 

 for larva pupating on April 22 to 14 days for one pupating on June 14, the 

 rearing being made in glass vials out-of-doors under natural conditions of tem- 

 perature. In 1909 the first moth emerged June 12 and the last July 25; in 

 3910 the first appeared May 29, the second June 6, and the last July 22. The in- 

 formation presented shows that the moths continue to emerge in spring during 

 a period of about a month and a half, which means that the larvse continue to 

 hatch out and enter the fruit for a similar period of time. Out of a total of 63 

 moths for which the date of emergence was kept during the spring of 1910, 35 

 emerged between June 20 and 25, or 3 weeks or more after the blossoms had 

 fallen. In the author's longevity observations several moths, both of the spring 

 and later brood, lived as long as 10 days, but the greater number died in 3 or 

 4 days. 



In 1910 eggs were first found June 15, at Guelph. It is estimated that for 

 the 2 seasons during which observations were made, approximately 80 per cent 

 of the first brood eggs were deposited on the leaves, 18 per cent on the fruit, 

 and 2 per cent on the twigs. Although eggs were sometimes found 6 or more 

 feet away from the nearest apple, in frequent, examinations of fruitless trees 

 situated near trees with fruit, a total of but 2 eggs was discovered. Thirty-six 

 was the maximum number of eggs observed to be deposited by caged moths. 

 The incubation period of the eggs during the early and later part of the season 

 averaged about 10 days. About 7 days were passed in the egg stage during the 

 warmest weeks, although in early August larvie were observed to hatch out in 

 as soon as 5 days. 



The average number of first-brood larvre entering apjjles through the calyx 

 was a little more than 75 per cent. Pears were found to have an even higher 

 percentage of calyx entrance than apples, counts for 1909 and 1910 showing 90 

 per cent entering in this way. The average period passed by larv* in the 

 fruit during July and August was found to be about 26 days ; in September and 

 October 50 or more days may be spent in the fruit. Attention is called to the 

 fact that in many cases the exit hole is situated in a different part of the fruit 

 from the entrance and that the presence of 2 worm holes in an apple does not 

 necessarily indicate that 2 larvte have entered it. 



In banding experiments made on 2 trees in 1909 in which a total of 621 

 larvae were collected, 10 times as many came up from the ground as came down 

 the tree, while in observations made on one tree in 1910 in which 150 larvae 

 were collected, 4 times as many larvae left the fruit after it fell as before. 

 Observations made in 1909 show that at Guelph the earliest larva leaves the 

 fruit between July 10 and 26. In the Niagara district the date is somewhat 



