256 Geiietical Studies in Moths 



later than filigrammaria. After allowing a reasonable time to elapse I 

 removed the pupae from the cages and deposited them for aestivation 

 in as natural a place as possible out of doors. They passed the summer 

 without loss and appeared in due course, their first representative 

 emerging seven days later than the earliest filigraminaria and ten days 

 earlier than the first autumnata ; in general it may be said that their 

 whole period of emergence formed a perfect transition between those of 

 the parental subspecies. 



Description of Larvae. 



As in filigrammaria the head was a dull smoky green. The ground 

 colour was an olive green just intermediate to the blackish green of 

 filigrammaria and the bright apple green of autumnata. The usual 

 three white and yellow longitudinal stripes were present but their 

 strengths varied,and agreed with thoseof neitherparent. \i\ filigrammaria 

 the order of the strengths of the stripes is (1) Subdorsal, (2) Spiracular, 

 (3) Supraspiracular ; in autumnata this is (1) Spiracular, (2) Subdorsal 

 and Supraspiracular equal ; in the F^ larvae the order was (1) Spiracular, 

 (2) Subdorsal, (3) Supraspiracular — an evident compromise. 



Ventrally, except that its ground is green, the markings strongly 

 suggest filigrammaria. 



On the whole the larva is clearly an intermediate to the dusky green 

 filigrammaria with its violent contrasts and the more subdued lighter 

 green autumnata with its less distinct stripes. 



Pupae. 



No obvious differences exist between those o{ autumnata and filigram- 

 maria ; naturally therefore none exist between either and the F^ lot. 

 Only one point needs to be emphasised and that is that there is no lack 

 of pupal viability shown, such as occurs in the F^ generation of the 

 0. autumnata (^ x 0. dilutata $ cross. 



Imagines. 



In making the original pairing a filigrammaria female with the two 

 central bars as well as that preceding the subterminal pale line well 

 developed was chosen, and paired with the usual pale grey pinewood 

 autumnata male with much weakened central bands and almost obsolete 

 basal lines, clouds and presubterminal band. From these parents I 

 reared what at first sight seems a nondescript brood quite incapable of 

 classification. Putting it alongside its cousins of both parent species 

 broad differences are obvious. The general impression gained from the 

 massed broods is that the F^ insect as a whole is (1) less silky than 



