216 
The Influence of Soil on the Percentage of Water Contained vm 
Potato Tubers. 
It has often been remarked that potatoes grown on sandy soil are 
superior in quality to those grown on clay soil. Our experiment 
carried on in the greenhouse, of which the details have been already 
given, gave us an opportunity to note the comparative amounts of 
moisture contained in the tubers grown on the two soils used. ‘The 
tubers grown in the sand contained 13.686 per cent. of water, and 
those grown in the potting soil 19.045 per cent., showing that the 
latter contained about thirty-nine per cent. more water. 
Wild Potato. 
We continue to grow the wild potato received in 1883, from Mr. 
J. G. Lemon, of Oakland, Cal. We have also grown a wild potato 
from Messrs. Landreth & Son, thought by them to be either Solanum 
Fendleri, or S. Jamesii. This was to all appearances, the same as 
that received from Mr. Lemon in 1883, which we believe has been 
thought by Dr. Gray to be only a variety of the common potato, and. 
named Solanum tuberosum Var. boreale. It is certainly very dis- 
tinct fromour common potato. The foliage is quite different in ap- 
pearance, and we have made repeated attempts to cross fertilize the 
flowers of the two without success. Neither the potato beetle nor its 
larvae has fed upon the foliage, the leaves were not affected by the 
blight, nor were any of the tubers decayed. Unplanted potatoes 
from the crop of 1884, are still (Oct. 30, 1885) sound, and the eyes 
have not started. The tubers have not perceptibly increased in size 
during the three generations of culture at the station. 
INSECTS AND INSECTICIDES. 
Experiments with the Squash Vine Borer. 
In our last report, we gave the results of certain experiments made 
with the view of discovering a preventive against the injury of the 
squash vine borer, Melittia cucurbitae (Harris). From these it ap- 
pears that corn-cobs dipped in coal tar, placed among the plants, 
seemed to have a marked effect in repelling the female insect. It 
also appears that Paris green mixed with water, and thus applied to 
the stems, and the kerosene emulsion applied in the same way, proved 
beneficial by reducing the number of borers. 
We have repeated the experiment with the cobs dipped in coal tar; 
and intended also to repeat the application of the Paris green and 
water, but the unusually vigorous growth of the vines made it al- 
most impossible to trace out the stems, or even to walk among them, 
without doing much injury to the plants. We, therefore abandon- 
ed this part of the experiment, after attempting the second applica- 
tion. Indeed the labor and care required to apply either the Paris 
green mixture or the soap emulsion after every hard rain, as would 
seem necessary, will prove an almost unsurmountable objection where 
the plants are vigorous. The coal tar remedy, however, is so easily 
applied, and the odor is so well retained, that it continues its influ- 
ence long after the ground is completely overrun by the vines. ‘The 
