92 



THE ENTOMOLOGIST S RECORD. 



It now becomes necessary to describe my series of tbe white forms 

 of the 5 , in detail. In all I have fourteen specimens. Of these 

 eight are of the extreme form, which resembles the spring brood 

 specimens of napi more or less closely on the upperside ; but under- 

 neath, one is of a pronounced napaeae form ; two are more or less as 

 in type napi ; and the remaining five approach closely to bryoniae, 

 having a deep tone of ground colour which would make them 

 remarkable if they were seen among the lowland race. 



Ninth in my series is a beautiful specimen with pure white 

 hindwings and the forewings heavily scaled with grey from the base to 

 the end of the discoidal ceil, and the whole length of the inner margin, 

 the usual apical marking being much extended ; underside as bryoniae. 



Tenth, a specimen lightly dusted with grey over all the wings, 

 with a very faint sprinkling of brown scales on the basal areas ; 

 underside napaeae form, but of a very pale coloration. 



The next three specimens are pronounced bryoniae forms, in white 

 and grey. The ground colour is only visible between the nervures of 

 the hindwings. but there is a slight dusting of brown in the grey 

 scaling: underside as bryoniae. 



The fourteenth specimen is a complete bryoniae form with the 

 ground colour only dimly visible here and there near the outer and 

 inner margins of the hindwings, and a faint brown scaling at the base 

 of the forewings. Underside as in bryoniae. The last four specimens 

 are exceptionally beautiful, and have the appearance of being slate- 

 coloured. 



I also have four specimens of a transitional form, with the ground 

 colour neither white nor yellow, and the scaling a mixture of grey and 

 brown. Although of a very extreme bryoniae form, they have a 

 lighter appearance than less heavily marked specimens of ordinary 

 bryoniae. Now, of the fourteen specimens just described, twice I took 

 two in one day, and the other ten were all taken separately in a number 

 of isolated localities, with a range in altitude of quite 2,500 ft., and on 

 dates ranging from May 11th to July 16th. To these can be added 

 one more white specimen which I saw but failed to catch, making a 

 total of fifteen. In every locality where I found these single speci- 

 mens, ordinary bryoniae occurred literally in dozens. It therefore 

 follows, that even if the individuals of the white forms were bred from 

 eggs laid by a white 2 , about ninety-eight per cent, of the brood must 

 have been true bryoniae, or have perished. Add to this the fact that 

 five out of eight of the extreme white specimens have tbe underside of 

 bryoniae, and one that of napaeae, and I think it seems most natural to 

 conclude they all are the offspring of bryoniae. 



Now any collector relying on such records as those already 

 quoted, on capturing this series would have recorded the first 

 eight specimens as type napi, and the other six as hybrids between 

 napi and bryoniae. Accepting this, it follows, of necessity, that 

 as Mr. Williams suggests napi and bryoniae " exist side by 

 side " in these localities right up to 6,500 ft. This does not 

 seem a very satisfactory theory, to say the least of it. But, let us 

 consider what it implies. In every locality where I took either the 

 supposed types or hybrids, as such their presence implies that a pure 

 strain of napi exists in that locality and must do so in moderate 

 numbers ; otherwise it must soon fail to maintain itself among the 



