16 BULLETIN 774, U. S. DEPARTMENT OF AGRICULTURE. 



Migration to the sunimer hosts, Phragmites and Tvpha, began the 

 last week in April and continued until August, the great body travel- 

 ing in early June. On these hosts about 10 generations took place, 

 continuing up to November. The vast majority of aphids to be found 

 during the summer were wingless, but winged parthenoparous indi- 

 viduals were also produced on the summer host plants and these 

 served to distribute the species among these plants. About the middle 

 of October and for six weeks succeeding, winged sexuparous migrants 

 and winged males were produced and these flew to the fruit trees 

 whereon the sexuparae proceeded to deposit sexual females. The 

 sexes were most abundant during the forepart of Xovember, and 

 were to be found as late as the middle of December. 



Oviposition took place throughout Xovember and December, the 

 majority of ova having been placed before December 10. 



The foregoing data are based on observations made at Walnut 

 Creek, Cal., between August, 1915, and December, 1916. 



LITERATURE CITED. 



1. Blakey, J. G. 



1918. The mealy plum aphis. [Hyalopterus pruni.] In Gardeners' 

 Chronicle, y. 63. no. 1619, p. 1-2, illus. 



2. GOOT, P. VAN DEE. 



1917. Zur Kenntniss der Blattlase Java's. In Contributions a la faune des 

 Indes Xeerlandaises, dirigees par J. C. Koningsberger, v. 1, fasc. 3, 

 p. 1-301, illus. Buitenzorg. 

 Page 125: Hyalopterus pruni. 



3. Lowe, V. H. 



1S97. Plant-lice : Descriptions, enemies and treatment. N. Y. Agr. Expt. 

 Sta. (Geneva) Bui. 139, p. 645-664. 

 Page 657 : Hyalopterus pruni Fab. 



4. Morris, Earl. 



1915. Cracking of prunes. In California State Com. Hort. Mo. Bui., v. 4, 

 no. 10, p. 476, figs. 99-100. 



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