304 MAINE AGRICULTURAL EXPERIMENT STATION. I915. 



( 1 ) The correlation between the egg production to March 

 I of the pullet year as one variable and the egg production up 

 to the time when the individual is 300 days of age as the second 

 variable is extremely high. 



(2) The mean production to March i is, in general, higher 

 than the mean production to 300 days of age. 



(3) The production to March i is a relatively less variable 

 measure (as indicated by the coefficient of variation) than the 

 production to 300 days of age. 



(4) The conclusion that the 300-day production would be a 

 better measure of the winter cycle of fecundity than the pro- 

 duction to March i is not warranted by the facts. Whatever 

 superiority there is of one of these measures over the other is 

 entirely in favor of the production to March i. We may 

 therefore conclude that the use, in the writer's investigations on 

 fecundity, of the record of egg production to March i of the 

 pullet year as a measure of the winter cycle of production is 

 fully justified by a critical examination of the facts. The justi- 

 fication for the employment of the winter cycle of production 

 as an index of innate fecundity capacity or ability is a distinct 

 and separate problem which has been discussed at length in 

 earlier papers. 



TWO CLOVER APHIDS.* 



Aphis brevis Sanderson (Lyong-beaked clover aphid). 



In the vicinity of Orono, Me., the leaves of the hawthorn 

 (Crataegus spp.) in June are commonly twisted into dark- 

 purple swollen curls and are inhabited by an aphid the fall 

 migrants of which were described by Prof. Sanderson as Aphis 

 brevis. This insect takes flight from hawthorn during June 

 and early July and returns late in the season before producing, 

 the sexual generation. I have taken the fall migrants on culti- 

 vated plum {Prunus spp.), but yet have made no spring col- 

 lections from that host. In June and July, 1906, I collected ap- 

 parently the same species from the twigs and terminal leaf 

 curls of the Japan quince (Cydonia japonica). 



*Th.is is an abstract of a paper with the same title, by Edith M. 

 P^tch, published in the Journal of Agricultural Research, Dept. of Ag- 

 riculture, Washington, D. C, Vol. Ill, No. 5, Feb. 15, 1915, pp. 431-433, 

 with 3 figures. 



