312 Journal of Agricultural Research voi. xviii, No. 6 



high. Occasionally, also, eggs of this species will be found on water- 

 sprouts; but this is not one of the favorite positions. 



The eggs are deposited between the fruit buds on the twigs, in the 

 little impressions occurring on the fruit spurs, in scars, etc., and even 

 exposed on the twigs and small branches. On small trees they may 

 be found occasionally in crevices of the bark on the trunk and main 

 branches. 



HATCHING 



During the spring of 191 5 eggs began hatching at Arlington Farm, 

 Va., about March 15. On March 16 a few scattered young were found 

 on the trees. At Vierma, Va., hatching began about March 27. A few 

 eggs hatched earlier than this, but these were so rare that they need 

 not be considered. In fact all the young which emerged before April 3 

 at Vienna died during a period of cold weather occurring from March 29 

 to April 2. 



The important hatching began, therefore, on April 3 and continued 

 till April 10. It was most rapid from April 5 to 7, nearly all the eggs 

 having hatched before the eighth. 



In connection with the early hatching which we have noted, it should 

 be borne in mind that eggs of this species may hatch at any time during 

 the winter, at least after about the first of January, in case warm tempera- 

 tures prevail for a period of four or five days. Such hatching frequently 

 occurs in the vicinity of Washington. 



STEM MOTHER 

 LENGTH OP NYMPHAL LH^E 



The average duration of the nymphal period was 13 days, 11 different 

 insects becoming adult just 13 days after hatching. A few attained the 

 adult condition in 12 days, while others required 14. The length of the 

 different instars varied considerably, this being due apparently entirely 

 to temperature conditions. In all cases under observation a long period 

 in one stage was compensated for by a short period in the following in- 

 star. In general the first instar was longest, requiring 4 or 5 days; the 

 second was shorter, 2 or 3 days; the third and fourth v>^ere about equal, 

 being between 3 and 4 days each. 



TOTAL LENGTH OP LIFE AND DURATION OP STEM-MOTHER PERIOD 



The total length of life of stem mothers varied from 23 to over 49 days, 

 the average for seven insects being 38.4 -f. The duration of the gen- 

 eration in 1915 was from April 3 to May 26. It should be noted that 

 while some eggs hatched as early as March 24 all the insects bom before 

 April 3 were killed by freezing temperatures. 



