16 BULLETIN 774, U. S. DEPARTMENT OF AGRICULTURE. 
Migration to the summer hosts, Phragmites and Typha, 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 November, and 
were to be found as late as the middle of December. 
Oviposition took place throughout November 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. Buaxey, J. G. 
1918. The mealy plum aphis. [Hyalopterus pruni.]) In Gardeners’ 
Chronicle, y. 63, no. 1619, p. 1-2, illus. 
2. GooTt, P. VAN DER. 
1917. Zur Kenntniss der Blattlase Java’s. In Contributions 4 la faune des 
Indes Néerlandaises, dirigées par J. C. Koningsberger, v. 1, fasc. 3, 
p. 1-301, illus. Buitenzorg. 
Page 125: Hyalopterus pruni. 
3. Lowe, V. H. 
1897. Plant-lice: Descriptions, enemies and treatment. N. Y. Agr. Hxpt. 
Sta. (Geneva) Bul. 139, p. 645-664. 
Page 657: Hyalopterus prum Fab. 
4. Morris, HAR. 
1915. Cracking of prunes. Jn California State Com. Hort. Mo. Bul. v. 4, 
no. 10, p. 476, figs. 99-100. 
ADDITIONAL COPIES 
OF THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENTG OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C. 
AT 
5 CENTS PER COPY 
Vv 
