102 THE entomologist's record. 



of the tj'pe and var. rustica. Of Brood II. (1915) F.l, I had more 

 than 40 males. These varied from a cream colour a little deeper 

 than any of my pure bred var. rxstica, though paler than some rustica 

 I have seen, to a creamy brown a good deal paler than that of any 

 typical male. Of Brood III. (1915) F.l T had six males, of which 

 three were no darker than my var. rustica, and three pale creamy 

 brown specimens. 



In 1916 from Brood IV., F.2, I bred only seven imagines, five 

 males and two females. Two of the males were quite as pale as my 

 var. rustica, in fact paler than many of them. One was beautifully 

 clouded with greyish brown scales on the fore- and hindwings, similar 

 to the var. rustica bred in 1914, and one was as dark as the darkest of 

 my var. stamlfussi, F.l, generation. Two pairings were obtaiueil with 

 two pale males and the two females (Broods I. and II., 1917, F.3), and 

 their offspring had the following constitution : - 



<? Brood II. ((? var. rustirax 2 type) ^ 

 <? (Brood IV.) 5 Brood II. {g var. rustica x 9 type) ^ 



„ (? Brood II. (t^ var. rustica x 2 type) 

 ? (Brood iV.) - ^^^^^ ^j_ ^^ ^^^. ^.„^^,-^,,x J type)- 



The ova were all fertile and the larv^ did well until late in their last 

 instar, when many became diseased and died. 



In the case of Brood I. (F.3) the ground colour of twenty of the 

 males was very pale, in some actually paler than in many of my pure 

 bred var. rustica. One was shaded with brown scales over the central 

 and posterior portion of the forewing and the whole of the hindwing, 

 especially in the internf-ural spaces, and the thorax was pale greyi.-h 

 brown. It resembled the var. rustica bred in 1914, and the male of 

 Brood IV., 1916, but was darker and more handsome than either. The 

 brood was fairly well spotted in the case of both sexes. 



In the case of Brood II. also the ground colour was pale. Six 

 males were no darker than my var. rustica and the rest were of various 

 shades of pale creamy brown. The darkest was about the same colour 

 as the middle specimen of Brood II. var. stavdfussi, F.l, arranged in 

 order of depth of colour. All were very lightly spotted, and in this 

 respect contrasted strongly with Brood I., in spite of their closely 

 related ancestry. 



Two males and one female had no marginal spots on the hindwings, 

 as in several F.l specimens of Brood II. The results show that no 

 segregation of the dark brown colour of the type form takes place either 

 in F.2 or F.3 generations. 



Many of the specimens of F.2 and F.3 are as light as var. rustica, 

 but in F.l generation some were almost as pale as the pure race, 

 whereas none were nearly as dark as the type form. Even with the 

 small numbers bred I think it is safe to say that the pale cob air of 

 var. rustica and the dark brown of the type do not behave as Mendelian 

 unit characters. With regard to breeding var. stajjdfussi, F.l, it can 

 be definitely stated that pairing was equally easy between either sex of 

 var. rustica and the type. 



Both crosses were equally fertile. In fact, fertility of the inbred 

 stock was complete until the experiment was given up owing to the 

 war, and the larvae appeared to be as vigorous as pure bred larvae. 

 Imagines emerged for the most part in the afternoon and evening, but 



i 



