﻿t THE ENTOMOLOGIST. 



females. Six weeks elapsed, and, as no other moths emerged, I 

 dng up the remainder of the pupae in this pot and also all of 

 those in the other ; practically every pupa was sound and 

 healthy. They were, therefore, laid aside, packed in moss as 

 usual, and a strict eye kept on them, but no further emergences 

 occurred until October, i.e. the normal time for the parents, 

 when the remainder of the dilutata <? x autumnata $ cross 

 came out and proved to be all males. The imagines of the 

 reciprocal cross emerged almost at the same time, and yielded 

 the sexes in equal proportions. In the case of the dilutata ^ 

 X autumnata 2 the sex proportions were 7 to 1 in favour of 

 the females. 



The imagines were curious-looking objects, which it is 

 impossible in many instances to describe or figure. I shall 

 confine myself, therefore, to the consideration of the points 

 usually relied upon, when present, to separate the two 

 species. 



I. — OpORABIA hybrid ROBSONI =: 0. DILUTATA <? X AUTUBINATA 2 . 



The dilutata males used to produce this cross were of the 

 melanic form, and the result has been that, in the case of 

 the females, the melanism has almost obscured the markings ; 

 on the contrary the males, although possessing a rather 

 brownish grey ground, are rather strongly and clearly marked. 

 These facts are of some significance, for it seems as if some 

 cross inheritance has occurred, for in the present forms, no 

 matter how melanic the specimens, the females are generally 

 clearly marked, whilst the males often bear confused 

 markings. 



It is absolutely certain that if the hybrid males were taken 

 wild and no preparations made of the genitalia, they would be 

 set down as a form of autumnata very little removed from the 

 ordinary ; just as certainly, except for the white V, derived from 

 autumnata, at the junction of vein two with the cell, the females 

 would be regarded as dilutata, although this dilutata appearance 

 maybe the result of the melanism present. I shall now proceed 

 to point out the distinctive characters of hybrid robsoni : — 



(1) The male antennce. The male antennae are distinctly 



intermediate between the fine antennsB of autumnata and 

 the more coarsely jointed ones of dilutata. 



(2) Line hounding basal area. 



(a) Male. Distinct, and forms a right angle as in autumnata. 



[b) Female. More rounded and nearer dilutata. 



(3) Band between basal line and that bounding central area. 



(a) Male. Practically obsolete or forming a suffusion as in 



autumiiata. 

 {b) Female. More band-like, as in dilutata. 



