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 prodromaria. In this I 

 was successful, and a (^ prodromaria 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 larvae 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 larvse 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 prodromaria. The pupae on the 

 other hand, so far as concerns the anal armature are much more 

 exactly intermediate. — T. A. Chapman, Firbank, Hereford. 



