WOOLLY APHID OF THE APPLE. 175 



the abdomen is found to be dark yellowish red or rusty brown. 

 These are the fall migrants that leave the apple and seek the 

 elm before giving birth to the generation of true sexes, — minute, 

 wingless, beakless creatures, the female of which deposits a 

 single "winter egg" within a crevice of the elm bark. I have 

 not yet observed under out-door conditions the return of the fall 

 migrant to the elm, but I have repeatedly during t\vo years 

 observed the spring migration from elm to apple and mountain 

 ash and the subsequent developm.ent of the summer colonies so 

 that there is no doubt that the species returns to the elm for 

 the deposition of the winter egg. The flight of the fall mi- 

 grants away from the apple is apparently a common observa- 

 tion of all who have studied this species either in this country or 

 abroad, with the exception of a statement* that in South Africa, 

 lanigera does not produce any alate forms at all in the fall. 



Where woolly aphid colonies are very thick, the true sexes 

 and the winter eggs are sometimes found upon the apple tree. 

 That such occurrences are accidental seems probable as fall 

 migrants of most species will occasionally dispose of their pro- 

 geny before reaching the appropriate winter host. 



A record of such an occurrence is to be found in the Report of the 

 Entomologist of the United States Department of Agriculture for the 

 year iSyg by J. Henry Comstock. On page 259 of this Report, Dr. 

 L. O. Howard recorded his observations made in a little orchard of 

 Russian apple trees then on the grounds of the Department of Agricul- 

 ture at Washington, his statement concerning the winter e%g being as 

 follows : 



"The winter egg was found on several occasions during the winter 

 in crevices of the bark over which a colony had been stationed during 

 the summer. It was a rather long ovoid, measuring .322 mm. (.125 inch) 

 m length and was very similar to the winter tgg of Colopha idmicola 

 (Fitch), as described by Riley in Bulletin No. i, Vol. V, Hayden's 

 Survey. 



"This egg was laid, as Professor Thomas supposes, by a wingless 

 female, differing from the ordinary agamic form to a certain extent. 

 These females we only know from finding their skins around the winter 

 egg, since they often die without depositing it. The males we have not 

 seen." 



Mr. A. C. Baker of the Bureau of Entomology wrote me (Nov. 20, 

 1912) : "I found that when the colonies are very thick the alate forms 

 often stay on the apple and I have found on one tree a number of 



*Moore: So. Af. Ag. Journal. Sept. 1912, p. 42S. 



