794 
Fig. 5. Pupa Cases of Cherry and Pear Slug. 
When disturbed these cells are very 
easily broken apart, a fact which might 
indicate that fall plowing can be used as 
a method of destroying the pupae, accord- 
ing to Marlatt. 
“During the heated season of July and 
August the transformation from the lar- 
val to the adult insect is quite rapid, the 
pupal stage being assumed in from six to 
eight days, and the adult flies transform- 
ing and digging out through the soil some 
12 or 15 days after the larva entered it.’’* 
According to the studies of Peck and 
Marlatt some of the larvae of this spring 
brood remain over in the soil until the 
following spring. This seems to be a pro- 
vision of nature to carry the species over, 
should anything happen to exterminate 
the regular line of succession, such as 
Fig. 6. 
Egg of Cherry and Pear Slug. 
—After Ewing. 
*C. C. Marlatt, U. S. Department Agricul- 
ture, Bureau of Entomology Circular 26, Second 
Series 1897. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
lack of food, 
ditions, etc. 
Natural Enemies 
Although furnished with a sticky cov- 
ering which acts as a repellant against 
all enemies, the insect is not entirely 
free from insect enemies, and in Europe 
some half dozen insect parasites have 
been reared from it. In this country a 
minute fly is said to sting the egg through 
the upper leaf tissue. 
unfavorable climatic con- 
Remedies 
White hellebore, one pound to 50 gal- 
lons of water. No foliage is injured and 
the slugs are nearly ail dead on the day 
following the application of spray. 
“Black leaf-40” gives practically the 
same results as white hellebore and does 
not injure the foliage. “Black leaf-40” is 
more expensive to use than the hellebore. 
Hellebore is the best remedy to use for 
cheapness, efficiency and lack of injury 
to the foliage. To get best results it 
must be fresh and free from adultera- 
tion. 
Arsenate of lead is cheaper but does 
not kill as quickly and may injure the 
foliage. 
CurcuLtio. See under Plum Pests. 
Divaricated Buprestis 
Dicerca divaricata 
A flatheaded borer found beneath the 
bark. May be treated the same as the 
flat headed apple tree borer, which see 
under Apple Pests. 
Dogday Cicada or Dogday Harvest Fly 
Cicada linnet 
Deposits its eggs in the twigs of cher- 
ry and other trees. The musical notes 
or drumming of the male cicada during 
the middle of the day is a familiar sound 
during August and September. Injury 
by this insect is generally slight and it 
is scarcely necessary to trim out and 
burn the twigs containing eggs. 
Emperor Moth 
Callosamia promethea 
Until late in September, full-grown 
caterpillars of the Promethea Emperor 
moth may be found feeding on the leaves 
of cherry, especially of the wild species. 
This is a large, bluish white, or bluish 
