68 General Notes. 
changes have been made in the names of common species. ——J 
Baker continues his synopsis of Tillandsiese in the November Jour- 
nal of Botany, reaching No. 112, with the article to be continued. 
In the December number of the same journal Otto Nordstedt 
points out that a great many of the figures in Cooke’s British Der- 
mids are copied from Ralfs, Archer, Brébisson, De Bary and 
many other authors, in spite of the statement that “the greater part 
of the figures have been drawn direct from the specimens them- 
selves.” We must suppose that the artist imposed upon the author 
in this case. G. Massee publishes in the December Grevillea a 
revision of Polysaccum, admitting eight species, of which two, P. 
pisocarpium and P. turgidum are American. 
ENTOMOLOGY. 
THE Hop PLANT-LOUSE, Phorodon humuli.—An important con- 
tribution to our knowledge of the life of this species was made 
during the year just closed, by the Entomologist of the U. S. 
Department of Agriculture. ’ Professor Riley, assisted by Mr. Per- 
gande, Mr. Howard, and others, very carefully traced the transfor- 
mations of the species throughout one complete cycle, i.e., from the 
winter eggs of one year to those of the year following. 
The most interesting result of these investigations is the confir- 
mation in a striking manner of the previously known fact that this 
species passes the winter on plum trees 
It is urged by Professor Riley that this is the only mode of hiber- 
nation of the species, or at least-that it does not winter on the hop. 
This is a point of the highest practical importance, and one which 
must be settled before a complete plan of defence from the ravages 
of this pest can be matured. Unfortunately, the evidence adduced 
by Miss Ormerod in her report for 1884, and indicating that one 
form of this species winters on the roots of hops, is too strong to 
be set aside by anything yet advanced, 
The following is a résumé of the transformations of this insect, 
as determined ie Professor Riley, and published in advance of his 
annual report’: 
“ As soon as Pian leaves put out in spring, the first generation 
of lice hatch from the winter eggs on plum. These are wingless 
agamic females, giving birth to young ike themselves without the 
intervention of males. The third successive generation upon plum 
however, is winged, not wingless, and the first fledged individuals 
1 This department is edited by Prof. J. H. Comstock, Cornell Univer 
sity, Ithaca, N. Y., to whom communications, books for notice, etc., 
sho uld be sent. 
2 L. O. Howard, The Cultivator and Country Gentleman, N ovember 
17, 1887. 
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