8 
the idea that species of commercial value might be found, and that per- 
haps something might be done in the way of cross breeding allied 
species, thus producing not perhaps a better quality of silk than that 
of the silkworm of commerce, but a hardier insect, which would 
require less artificial attention and at the same time would be more 
resistant to disease. The whole experimentation, we believe, was sug- 
gested by the disastrous prevalence in the silkworm establishments of 
Europe of the pebrine disease, which some years later was controlled 
by virtue of Pasteur's discoveries. 
In the course of this work Professor Trouvelot brought over from 
Europe living specimens of different silk-spinning caterpillars in differ- 
ent stages of existence. Among others he imported living egg clusters 
of the Gipsy Moth. He lived at No. 27 
Myrtle street, Medford, and the insects 
escaped from his window into the adjoin- 
ing garden. One story is that the eggs 
blew out of the window, and another that 
the caterpillars crawled out. He seems, 
however, to have done what he could to 
repair the damage, gave public notice of 
the escape of the species, and undoubt- 
edly searched carefully for the missing 
eggs or larvre. Unfortunately, the part 
of Medford in which he lived almost 
immediately adjoined an extensive wood 
lot, densely covered with underbrush, 
and in this jungle of vegetation the in- 
sect soon established itself. For many 
years, however, it was not noticed by 
the citizens of Medford, from which it 
is plain that it increased with extreme 
slowness. The principal reasons for this 
slow increase are supposed to be, first, 
that the insect was gradually accommodating itself to the severe cli- 
mate; second, that the wood lot abounded with insectivorous birds, 
and, third, that almost annually it was burned over. That there was, 
however, a constant, though slow, increase is shown by the fact that 
after twelve or fifteen years the caterpillars began to be troublesome 
in the gardens of the residents of that portion of the town. 
They fought it vigorously and undoubtedly retarded its increase by 
their individual activity, but by the summer of 1889 it had multiplied 
to such an extent as to become a notorious pest. In that summer its 
numbers were so enormous that the trees were completely stripped of 
their leaves, the crawling caterpillars covered the sidewalks, the trunks 
of the shade trees, the fences, and the sides of the houses, entering the 
houses, and getting into the food and into the beds. They were killed 
Fig. i Pupa of Gipsy Motli 
size (from Insect Life) 
-natural 
