BAG-WORM MOTHS. 103 
ular, brown and very thin-shelled cocoons, inside of which 
they hibernate as caterpillars, which do not transform to 
pupa until late in spring, and which soon afterward leave 
the cocoon, as moths, by round holes covered with perfectly 
fitting lids. 
FAMILY PSYCHID.X OR BAG-WORM MOTHS. 
As far as known none of these peculiar moths occur in 
Minnesota, though the writer has repeatedly received the 
peculiar bags from nurserymen, who had detected them on 
stock received from more southern states. The caterpillar 
builds for itself a silken sack covered with little twigs or 
bits of leaves. In this bag, which is made as soon as the 
worm hatches from the egg, it lives as in a house; it drags 
Fig. 101.—-Thyridopteryx ephemerxiformis Steph ; a,caterpillar; b, male pupa; 
c, female adult; d, male; e, female nupa filled with eggs; f, caterpillar in bag; g, 
young caterpillars carrying bags. From Div. of Entomology, Dep. of Agriculture. 
it always with it like a snail, and fastens it by strong silken 
cables wherever it intends to feed. For the sake of those 
interested in the study of lepidoptera the bag of the common 
bag-worm (Thyridopteryx ephemereformis Steph.) is 
shown in Fig. 101. 
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