are two barbed, club-shaped, brown tubercles on top of the 
second thoracic segment and two smaller ones armed with spines 
on the top of the others. There are two generations per year. The 
two related species, L. arthemis (Drury) and L. astyanaz (F.), 
are found on poplar, willow, birch, black cherry, apple, and bass- 
wood. The caterpillars are similar in appearance to those of 
L. archippus. 
Asterocampa clyton (Bdv. & LeC.) occasionally seriously de- 
foliates hackberry in the Lake States. Full-grown caterpillars are 
25 to 37 mm. long. The body is greenish except for a yellow stripe 
down the back and a deep blue, yellow-bordered stripe on each 
side. The head is armed with branched, antler-like spines, and 
there are two projections at the posterior end of the body. A. 
celtis (Bdv. & LeC.) is also abundant occasionally on hackberry 
in the Lake States. The caterpillar is greenish with a row of 
yellow dots down the back and three yellow lines along each side. 
Otherwise, it resembles the caterpillar of A. clyton. Langlois & 
Langlois (449) discussed its life history. 
FAMILY HESPERIIDAE 
SKIPPERS 
Members of this family are commonly known as skippers be- 
cause of the way they flit or dart from place to place. They are 
distinguished by the head which is nearly as wide or wider than 
the thorax, and the antennal club which usually has two pairs of 
spurs. The larvae usually have large heads and strongly con- 
stricted necks. They are also usually solitary, each one concealing 
itself under part of a leaf which it cuts and folds over. 
The silver-spotted skipper, HE pargyreus clarus (Cramer), one of 
the largest species in the family, is widely distributed throughout 
the United States and southern Canada, and the larvae feed on 
black locust, ground nut, and wisteria. Adults are brown except 
for yellow and white triangular spots on the forewings. The fore- 
wings are elongate, and the hindwings have rounded tips. Full- 
grown larvae are nearly 50 mm. long. The body is leaf-green; 
the head dull red except for two yellow spots on the lower part of 
the face; the neck and sides of the first thoracic segment are red; 
and the cervical shield is black. The body is also marked with five 
black rings. 
The larvae feed from within nests made by tying several leaves 
together with silk. Sometimes they cause heavy defoliation locally. 
Pupation takes place in loose cocoons spun among the leaves, 
usually on the ground. In the South there are two generations per 
year. Farther north there may be only one or one and a partial 
second. 
FAMILY SPHINGIDAE 
SPHINX MOTHS 
The adults of this family are distinctive in appearance and are 
known by such common names as sphinx moths, hawk moths, and 
hummingbird moths. They have stout, spindle-shaped bodies and 
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