180 SPAN-WORMS.; 
THE THREAD-BEARING SPAN-WORM. 
(Microgonia limbaria Haw.). 
This moth, formerly called Nematocampa filamentaria, 
is produced froma very singular caterpiliar, which is not un- 
commonly found upon the plum, apple, crab-apple, oak, hazel, 
strawberry and other plants, showing that it is a very gen- 
eral feeder. It measures not quite an inch in length, is of a 
grayish color, with dusky and blackish streaks, and bears 
on the posterior part of the fifth and sixth segments a pair 
of long, curved and fleshy horns, two of which extend for- 
ward and two curve. backward (Fig. 182). The head is 
Fig. 182.—Microgonia limbaria Haw. From Div. of Entomology, 
Dep. of Agriculture. 
brown, and there are two short brown tubercles on the pos- 
terior part of the fourth segment, and two small gray warts 
on each of the segments behind, those on the eleventh being 
most prominent. As soon as this queer-looking insect has 
reached its full size it constructs a slight silken cocoon, com- 
posed of pieces of leaves fastened together with silken 
threads, and inside this shelter it changes to a reddish-gray 
or pale-brown pupa. About ten days later the perfect insect 
escapes. 
This is a small moth of a pale ochreous color, marked 
with reddish-brown lines and dots, with a ring on the discal 
space, just beyond which is a dark lead-colored band, which 
becomes an almost square patch on the inner angle, and is 
continuous with a broad band of the same color on the 
