200 SCIENCE PROGRESS. 



64 per cent, of lugens. In the 1890 broods, all of whose 

 ancestors were lugens for two generations, the proportion 

 of tau had fallen to a little over 1 1 per cent, in one and a 

 little under the same figure in the other. Tn each of the 

 five cases about twice as many females as males were of the 

 tau form. Hence, as Standfuss puts it, it is more difficult 

 to transform the female of Aglia tau than the male. 1 



5. Grammesia trigrammica Hufn. <$ and do. ab. bilinea 

 Hb. ?. The female bilinea, taken by Gross at Garsten in 

 Austria, laid eggs of which the male parent was pre- 

 sumably a normal G. trigrammica. Of the sixty-seven per- 

 fect insects that resulted, thirty-eight were trigrammica 

 and twenty-nine bilinea. There were no intermediates. 



6. Anger ona prunaria L. 6. and do. ab. sordiata 

 Fuessl. ? . This cross, procured by Zeller, gave seventeen 



prunaria and fourteen sordiata. 



7. A. prunaria ab. sordiata $ and A. prunaria ?. 

 This cross, also obtained by Zeller, gave eighty-four of 

 prunaria to sixty-eight of sordiata, i.e., as in the reciprocal 

 cross, about 55 per cent, of the type and 45 per cent, of the 

 aberration. In neither of these cases were there any inter- 

 mediates. 



8. A. pminaria ab. sordiata S and ? . Among a large 

 brood reared from the eggs of a pair of normal A. prti- 

 naria, there appeared three males and two females of the 

 aberration sordiata. From a pair of these Standfuss ob- 

 tained thirteen prunaria (three $ and ten ? ) and forty-two 

 sordiata (twenty-four o* and eighteen ? ). Again there were 

 no transitional forms. 



9. Amphidasis betularia L. S and do. ab. doubledayaria 

 Mill. ? . A female doubledayaria found by Steinert near 



the "tricolour" and "non-tricolour" hounds, though there are different 

 degrees of development of black in the " tricolours " which may be com- 

 parable with the range of variation between "fere nigra " and " nigerrima " 

 in lugens. It is noticeable that in the case of S. lubricipeda and do. ab. 

 zatima (supr. p. 197), the reciprocal crosses do not afford evidence of male 

 prepotency. The numbers, however, are small. 



1 Compare the result of the cross between P. monacha $ and ab. 

 eremita ? . Here the typical monacha form was retained by twenty females 

 and only two males. 



