4. A Note on the Vitality and Longevity of Silkworm 
Moths during the Cold and Rainy Seasons in Bengal. 
By Mauve L. Cusenory, F.L.S., F.E.S., F.Z.8. 
(With Plates III—IV.) 
For some time past I have been working on the improve- 
ment of silkworms in Bengal by selection for longevity and 
immunity from disease, but not till about three vears ago were 
experiments able to be done ona large scale. When dealing with 
several hundreds of individuals in each generation I noticed 
that on the whole the moths lived very long during the cold 
seasons, fairly long in the hot weather, but only a very few 
days in the rainy season. This rise and fall in the vitality 
scale. I have also found when selecting for longevity that 
longer than the mated ones of the same generation. Silkworm 
moths, whether mated or not, usually lay their eggs a day or 
two after they have cut out of their cocoons, and I found that 
the unmated females usually live longer than the unmated 
male moths. 
which the long and short-lived moths use up their fatty 
reserves would also be of interest. However, I have to defer 
these experiments till later. 
The family Bombycidae, to which the silkworm moth 
belongs, and the family Saturniidae, to which the well-known 
peror moth and Atlas moth belong, unlike other Lepidop- 
tera, lack a proboscis; in fact they have no buccal orifice 
ov 
on their fatty reserves. Another characteristic, which makes 
silkworms in India well adapted for experimental investigation, 
is that the Indian varieties are many brooded. They have 
eight or nine generations during the year, completing about 
