116 
poured over the surface. This method is, however, of little value as 
compared with that above described, since it attracts malés in very much 
greater proportion than females—sometimes fifty of the former to one 
of the latter. It is also inef ffeetive on moonhght nights, and when the 
weather is cool or windy; is much more expensive; and, under the 
most favorable circumstances, less thoroughgoing. Its effect is shown 
by office notes made in 1888 and 1891. June 9 of the former year one 
hundred and twenty-seven beetles were caught in a pan fifteen inches 
across partly filled with water and kerosene, above which an ordinary 
lantern was suspended, the apparatus being placed on a bench under 
trees, in Urbana, Ill. A similar experiment, made May 7, 1891, with a 
tub of water and oil and a common kerosene lamp yielded 1,290 beetles, 
of which all but forty-one were males. In this case the trap was placed 
in a small forest plantation on the University farm at Urbana. ‘These 
beetles were all taken between 7:45 and 9:15 p. m., after which only 
now and then one would come to the light. Later in the season no 
doubt the proportion of females to males would have been greater; but 
statements made in another part of this article, under the head “Life 
History and Habits,” show that the disproportion continues throughout 
the season. 
The spraying of trees most resorted to for food is a possible meas- 
ure, since the beetles are killed by arsenical poisons—a fact demon- 
strated by laboratory experiments made by us in f888 with oak leaves 
dipped in Paris green mixture, one ounce to twenty gallons of water. 
The expense of a general application of such an insecticide will, however, 
prevent its common use. 
When pigs can be turned, in May and June, into groves, orchards, 
or forests infested by the beetles, they cannot fail to destroy immense 
numbers of them, since they eat them eagerly, and can easily find them, 
hidden as they commonly are by day barely under the surface of the 
ground. This is a measure only occasionally applicable. 
Remedial Measwres.—Direct remedies for the attacks of white 
grubs are either inapplicable to the corn field, are of doubtful economic 
value, or are too little understood, as yet, to make them worthy of recom- 
mendation. For example, kerosene emulsion may properly be ap- 
plied to infested lawns, and, if followed by a copious watering, may kill 
large numbers of the grubs, but the cost of this material and treatment 
will preclude its use against grubs in corn; and kainit and other potash 
fertilizers (the sulphate especially) will destroy grubs in the earth, but for 
this purpose must be used at a rate inadmissible in farm practice— 
more than a ton per acre according to Prof. Perkins (Fifth Ann. Rep. 
Vt. Agr. Exper. Station, p. 152). 
Among remedial measures of uncertain value may be mentioned the 
cultivation and dissemination of the fungus parasites of the white grub 
—uneertain because not yet thoroughly tested, and because such tests as 
have been made do not demonstrate the practical utility of the method. 
These parasitic fungi do, however, sometimes spontaneously de- 
strov immense numbers of white grubs in the field, and some of them 
ean be easily cultivated in quantity outside the body of the imseet— 
almost as easily as mushrooms may be grown for the market. The sub- 
ject of the fungous diseases of these insects is therefore a very suitable 
