96 Farmers’ Bulletin 1169. 
(6) Leaves eaten by green looping caterpillars or measuring worms__-- 
Spring cankcerworm, p. 36. 
(7) White, frothlike egg masses on tree trunk; leaves more or less eaten 
by yellow caterpillars with black and red hair pencils on back__---~_~ 
White-marked tussock moth, p. 41. 
(8) Leaves blistered or eaten by coiled, yellowish-white worms with 
black line alone, back——=— === Large elm sawfly, p. 51. 
Borers. 
(1) End leaves turning brown and falling in summer; tops and branches 
fail to leaf in spring; trunk and branches show patches of dead, easily 
peeling bark with burrowing, roundheaded grubs beneath it__________ 
Elm borer, p. 55, 
(2) Twigs wilt and break off, bark splits open, showing ugly scars; chips 
and matted excrement at entrance to burrow on twig or trunk___-~~ 
Leopard moth, p. 68. 
(3) Girdled twigs hanging on trees or lying on ground below trees_____- 
Twig girdler, p. Tl. 
Sap suckers. 
(1) Young bark more or less covered with brown or gray, elongate, 
more or less curved, shell-like bodies, readily raised with knife point 
Oreciingertwnall 2 2 Ss eee eee ee ee Oyster-shell scale, p. TT. 
(2) Bark on trunk or branches bearing larger or smaller rough, white, 
meal-cOvereds knots == = sane ee Woolly elm bark aphis, p. 88. 
(3) Branches and trunk, especially at crotches, more or less crowded 
with stationary brownish insects bordered by cottony white_-___-—-~- 
Buropean elm scale, p. 82. 
(4) Cockscomblike growth on leaves_____-___________ Gall aphids, p. 88. 
GUM, SOUR. 
Borer. 
Girdled twigs hanging on trees or lying on ground below them___-_~-____ 
Twig girdler, p. T1. 
GUM, SWEET. 
Leaf chewer. 
Leaves being eaten by caterpillars with blue head and silvery, diamond- 
shaped spots along the back —_____----___- Forest tent caterpillar, p. 35. 
HACKBERRY. 
Leaf chewers. ‘ 
(1) Leaves partly or entirely eaten by spiny, black, red-marked, cater- 
pillars up) tor2 inches Monge eee Spiny elm caterpillar, p. 48. 
(2) Leaves being eaten by green caterpillars with pale spots and lines 
along back and projections on’ head and rears- 29) eee 
Caterpillars of hackberry butterflies, p. 49. 
Galls. 
On leaves and twigs growths (galls) of various shapes and sizes__________ 
Hackberry gall insects, p. 91. 
HICKORY. 
Leaf chewer. 
Leaves being eaten by gregariously feeding caterpillars which, when full 
grown, are black, covered with dirty gray hairs, and nearly 2 inches 
lon Pee, See eee eee Walnut caterpillar, p. 46. 
Borer. 
(1) Leaves eaten at base of stem; tree sickly, bark inside and surface of 
outer wood with centipede-like engravings__Hickory barkbeetle, p. 72. 
(2) Girdled twigs hanging on trees or lying on ground below trees__--_- 
Twig girdler, p. T1. 
Galls. 
Abnormal growth on leaves and leaf stems________-_ Gall aphids, p. 90. 
Sy “ 
ony is. 
