108 TREE-HOPPERS. 
although in this respect the prevailing winds and other condi- 
tions influence the insect. The eggs are deposited quite as 
readily in the new growth of old trees as in young trees, but 
the damage is much more noticeable in the latter case. The eggs 
are placed in small compound groups arranged in two nearly 
parallel or slightly curved slits extending in the direction of the 
twig about three-sixteenths of an inch in length, and separated 
by one-eighth inch or less of bark. Facing either toward or 
away from the trunk, the female makes with its ovipositor a 
slightly curved slit through the outer bark, cutting in a direction 
posterior to the insect, so that the ovipositor, which is at first ex- 
Fic. 100a.—Ceresa bubalus Fab. Twig ofapple showing: a, female at work; b, 
recent egg punctures; c, bark reversed with egg in position, slightly enlarged; 
d, single row of eggs, still more enlarged; e, wounds of two or three years 
standing on older limbs (adopted from Marlatt). After Insect Life, Division of 
Entomology, Dep. of Agriculture. 
tended nearly at right angles to the body, at the completion of 
the slit, lies almost against the abdomen. The eggs are inserted 
very obliquely through the bark and nearly at right angles to 
the twig, immediately after the completion of the preliminary 
incision, beginning at the end of the slit last made, and are thrust 
well down into the cambium layer between the bark and the wood. 
A period of from one-half to two minutes is required for the 
insertion of each egg, after which the ovipositor is partially with- 
