SPAN-WORMS. 199 
der; they are deposited in regular masses, side by side, and as 
many as a hundred together. In most cases they are laid in 
exposed situations on the twigs or branches of the tree 
selected. They hatch about the time when the young leaves 
of the apple just expand, and this delicate food is greedily 
devoured by the young worms which cluster upon them. 
Here they enjoy life, being well hidden by the still small and 
curled leaves. The young caterpillar is pale olive-green 
with a pale head and cervical-plate. Mature, it reaches a 
length of about an inch. The caterpillars vary greatly in 
color, from greenish-yellow to dusky or even dark brown; 
they have broad longitudinal yellowish or paler stripes 
along their sides. Like nearly all loopers they assume when 
eet eteetiac ie vane ercicw, acai neta by emaconeter 
d, one joint of same. From Diy. of Entomology, Dep. of Agriculture. 
not feeding a stiff posture, either flat or parallel with the 
twigs on which they rest, or at an angle of about forty-five 
degrees. In this position, kept up for many hours at a time, 
they so closely resemble in color and shape a small twig 
that they are not readily detected. When full grown they 
either descend the tree on foot, or they let themselves down 
from the branches by silken threads. When thus suspended 
in great numbers, as is frequently the case, they become a 
