SCIENTIFIC NOTES. 
83 
Otherwise than not only distinct in every species but unvarying in its 
form. At the same time I am not prepared to deny that there may 
be exceptions to this difference and its constancy, although I do not 
think that it is probable. A more extended and exhaustive study of 
this subject than has yet been made will alone demonstrate this. That 
post mortem alterations of form take place in the armature is a sup- 
position that may be dismissed as impossible. The armature consists of 
hard chitinous plates which do not change their shape in drying any 
more than do the elytra of an ordinary beetle. — 'F. Buchanan White. 
On Hybridising Amphidasys prodromaria and A. betularia. — 
In this matter I can record from one point of view a great success, 
from another a disastrous failure. The experiment is so interesting 
that it will doubtless be followed up by others with more leisure and 
capacity to bring it to a successful issue than I unfortunately have, 
and it may be of assistance if I record my own experiments. I 
have bred prodromaria for several years, and it occurred to me to 
ascertain whether it would cross with betularia ; so in the spring of 
1890 I obtained some pupae of that species and forced them in order 
to bring about their emergence along with prodro7iiaria. In this I 
was successful, and a prodro77iaria paired with a large black $ 
betularia^ which laid a large number of eggs which proved to be 
fertile. These hatched and fed up well at first on sallow, afterwards 
on oak, and were as healthy and thriving a brood of larvse as one 
would wish to see. Some half dozen of them did what I have not 
met with in prodromaria (I have reared few betularia)^ viz.^ omitted 
a moult, and assumed the last skin one moult earlier, and 
not feeding up to full size, pupated rather earlier than the 
others. On looking at these in early spring, I found the moths had 
emerged during the winter, and somewhat damaged, had died. The 
mass of the brood from want of attention became unhealthy, as did 
also prodromaria and some other larvae I had, and in the result only 
a dozen produced healthy pupae. And here again I made a mistake, 
I endeavoured to force these in March to bring them out with 
prodromaria, but instead of taking to this treatment kindly as betularia 
does, they refused to be forced. One or two are still alive showing 
no signs of emergence ; the rest appear to be dead. In forcing 
pupae, it happens not unfrequently, more with some species than with 
others, instead of yielding, they appear to conclude that they have 
missed their proper season, that full summer is upon them, and that 
they must tide over till the following season. Probably this could be 
avoided by a proper graduation of temperature suitable to each species. 
This, however, was the result of the experiment with the hybrids. 
This spring I repeated the attempt to get hybrid eggs and had several 
hybrid pairings ; these all proved to be infertile, but as all my pro- 
dromaria proved also to be infertile except one batch, I attribute this 
result not to any infertility due to hybridisation, but to the fact that 
my prodromaria were in the fourth year of their domestication, and 
were also as already noted, not a healthy brood. The larvae of the 
hybrids were not exactly intermediate between 'those of the two 
parents but consisted of a majority much more like betularia and 
a minority that closely resembled prodro7tiaria. The pupae on the 
other hand, so far as concerns the anal armature are much more 
exactly intermediate. — T. A. Chapman, Firbank, Hereford. 
