THE WHITE-MARKED TUSSOCK-MOTH. 33 
rather slender and not covered with long hairs. She has consequently 
no power of flight, and is barely able to walk. After working her way 
out of the chrysalis and cocoon she takes her place on the outside of 
the latter and patiently awaits the approach of the male. Here she 
also deposits and protects her eggs in the manner already mentioned, 
after which she drops exhausted to the ground and perishes. The 
white mass covering the eggs is at first viscous, but soon dries, becom- 
ing brittle, and is impervious to water. 
Hibernation.—The species hibernates normally in the egg state, but 
occasionally a living chrysalis may be found in winter time. On Janu- 
ary 30, 1874, we received from Mr. Hunter Nicholson, from Knoxville, 
Tenn., a newly-hatched female, and this had, no doubt, prematurely is- 
sued from a hibernating chrysalis. This is, however, quite exceptional, 
and the different climatic conditions to which the species is subjected in 
its wide distribution do not seem to alter the normal mode of hiberna.- 
tion. 
Number of Annual Generations.—In the latitude of Washington the 
Species is two-brooded, the imagos of the first generation appearing in 
the first part of June, those of the second generation in September and 
October. On several occasions we have found, however, that a portion 
of the caterpillars from one and the same batch of eggs would be feed- 
ing while the rest had already transformed to imagos. The result of 
this retardation and irregularity in development is that caterpillars 
may be found continuously throughout the season from June till Octo- 
ber, and that there is, consequently, no distinct dividing line between 
the two generations. In the more northern States the species is single- 
brooded, the caterpillars appearing in the months of July and August. 
FOOD PLANTS. 
This caterpillar has most often been referred to by writers on eco- 
nomic entomology as injurious to fruit trees, such as Plum, Pear, and 
more particularly the Apple; but it also attacks a great many shade 
trees, and has been for many years particularly injurious to the elms 
and the soft or silver maples in some of our larger New England cities. 
It has also a predilection for old or large trees. 
NATURAL ENEMIES AND PARASITES. 
The fact that the caterpillar makes no effort to conceal itself shows 
that it enjoys immunity from enemies, and notably from birds. In fact, 
the American Yellow-billed Cnekoo, the Baltimore Oriole, and the Robin 
are the only birds which have been observed to feed upon the larve. 
Predaceous insects are also not particularly fond of this hairy caterpillar, 
the well known Wheel-bug (Prionidus cristatus, see Fig. 16) and a few 
other Soldier-bugs being the only species which occasionally suck its 
