thrived wonderfully well, and I might say they thrived too well, as they
grew so fast and became so voracious that the growth of the lilac trees
could not keep pace with the growth of the worms. These, at the fourth
stage, became so large that the foliage was entirely devoured, and, of
course, the consequence was that all the worms were starved. I only
heard of the result of that experiment long after the death of the
larvae; otherwise I should have suggested the use of another plant after
the destruction of the foliage of the lilacs; the privet (_Ligustrum
vulgare_) might have been tried, and success obtained with it.

Of such species as _Attacus pyri_, of Central Europe, and _Attacus
pernyi_, the North Chinese oak silkworm, which I have mentioned in my
previous reports, and bred every season for several years, I shall only
say that I never could rear Pyri in the open air in London, up to the
formation of the cocoon. As to Pernyi, I had, in 1881, an immense
quantity of splendid moths, from which I obtained the largest quantity
of ova I ever had of this species. I had many thousands of fertile ova
of Pernyi, which I was unable to distribute. Many schoolboys reared
Pernyi worms, but with what success I do not yet know. The number of
fertile ova obtained from Pyri moths was also more considerable than in
former years, which was due partly to the good quality of the pupae, and
partly to the very favorable weather in June, at the time the pairings
of the moths took place.

Leaving these, I now come to the North American species.

_Telea polyphemus_.--As I have stated in former years, this is the best
North American silkworm, producing a closed cocoon, somewhat smaller
than that of Pernyi, but the silk seems as good as that of Pernyi.