108 
THE PERIODICAL CICADA. 
of the suiroundinfi: wood, there remains in the center of the twig a 
dead spot, and the wliite ghstening egg shells of the escaping larvae 
liave been found in place six years after they have been inserted in 
the twig by the female Cicada. 
Considerable danger follows the work of the Cicada, in that as long 
as the wounds remain open or as dead spots on the limbs they are not 
only a source of weakness in the case of winds, but the}' offer attract- 
ive situations for the attacks of various wood-boring insects. If left 
to themselves the limbs migh"^entirely recover, except for the scars, 
but the borers gaining entrance through these spots complete the work 
Fir,, -i:^.— Periodical Cicada scars in hard-maple twigs after seventeen years. (Hopkins.) 
of destruction wliicli the Cicada began. Furthermore, such open 
wounds or pockets ui the twigs of fruit trees Doctor Hopkins has 
shown to be favorite points of attack for the woolly aphis {Schizon- 
cura lan'igera Ilausm.), the presence of which not only prevents the 
wounds from healing but causes additional abnormal growth, adding 
considerably to the injury to the branches, and making them more 
lia])le to tlie attacks of other insects. 
