INSECTS INJURIOUS TO THE OAK. 35 
except that leading into the lateral twig. It is probable that in many of these in- 
stances the limb broke when the worm was in the act of gnawing it asunder, either 
from its own weight or from a wind arising whilst the work was in progress. And 
even though the worm may have withdrawn into its hole and plugged the opening 
behind it, it is frequently discovered here, probably, and devoured by birds. After a 
violent wind in the summer season, some of our insect-eating birds may always be 
noticed actively in search of limbs and trees that have thereby been broken, their 
instinct teaching them that this breakage usually occurs from the wood being weak- 
ened by the mining operations of worms therein, Whose lurking places are now opened 
tothem. And they will be seen industriously occupied in picking around the fractured 
ends of the wood, and feasting upon the grubs which they there find. Numbers of 
our wood-boring larvee are thus destroyed, and the oak pruner, notwithstanding the 
precautions it takes to secret itself, doubtless frequently falls a prey to these sagacious 
foragers. 
Remedies.—These insects will undoubtedly at times occur in such numbers as to 
render it important that they be destroyed, at least where they resort to the peach 
or other valuable trees. And this may readily be effected by gathering and burning 
the fallen limbs in the winter or the early part of spring. 
24. THE SEVENTEEN-YEAR LOCUST. 
Cicada septemdecim Linn. 
Order HEMIPTERA; family CICADARLE. 
Stinging the terminal twigs of the oak and other forest trees and of varions fruit- 
trees, the seventeen-year locust, which deposits its long slender eggs in a broken line 
along the twig. 
Without attempting to recapitulate the history of this famous insect, 
we would only say that the eggs are deposited from the end of May 
through June (Fig. 9, d, e,) in pairs in the terminal twigs of the oak, &e. 
The larve (Fig. 9,7,) hatch out in about six weeks after they are depos- 
ited, and drop to the ground, in which they live, sucking the roots of 
trees, &c., for nearly seventeen years, the pupa state (Fig. 9, a, b) last- 
ing but a few days. 
The following remarks on the habits of this insect are taken from our 
Third Report on the injurious Insects of Massachusetts : 
As regards the kinds of trees stung by the Cicada I may quote from a communication 
from William Kite in the American Naturalist, vol. ii, p. 442, as confirming and add- 
jag somewhat to Dr. Harris’s statements: ‘‘ Seeing in the July number of the Naturalist 
a request for twigs of oak which had been stung by the so-called seventeen-year 
locust, I take the liberty of sending you twigs from eleven different varieties of trees 
in which the females have deposited their eggs. I do this to show that the insect 
seems indifferent to the kind of wood made use of as a depository of her eggs. These 
were gathered July 1, in about an hour’s time, on the south hills of the ‘Great Chester 
Valley,’ Chester County, Pa. No doubt the number of trees and bushes might ,be 
much increased. The female, in depositing her eggs, seems to prefer well-matured 
wood, rejecting the growing branch of this year, and using the last year’s wood and 
frequently that of the year before, as some of the twigs inclosed will show. An or- 
chard which I visited was so badly ‘stung’ that the apple trees will be seriously injured, 
and the peach trees will hardly survive their treatment. Instinct did not seem to 
caution the animal against using improper depositories, as I found many cherry trees 
had been used by them, the gum exuding from the wounds, in that case sealing the 
eggs in beyond escape. 
