294 The Inheritance of Wing-Colour in Lepidoptera 



The larvae were kept in the usual way in glass cylinders, and were 

 fed on lilac throughout the summer. They feed rather slowly, but when 

 ready to pupate, pieces of bark should be supplied, on which they can 

 make their cocoons. If more than about twenty insects were placed to 

 pupate in a single cylinder, a tendency was observed on the part of the 

 larvae to congregate in a small area, so that when finished, their cocoons 

 formed a continuous layer. As a consequence of this it was found that 

 where insects were surrounded by other cocoons they were often unable 

 to force their way out. It has been observed before that this species 

 will produce a partial second brood when in captivity, though it must 

 be rather unusual for an insect which as a rule hibernates in the pupal 

 state, to do so in the larval state as well. Insects that remain as pupae 

 during the winter begin to emerge as a rule in April or May, pairing 

 and laying freely. Some of the larvae resulting from these eggs will if 

 well fed pupate and emerge towards the end of July. These again 

 pair and lay, giving rise to a second generation, which, if properly fed, 

 and not kept too cold, often pupate before the end of the year. 

 Such insects emerge in May of the following year, rather later than 

 those insects which failed to emerge in July of the year before, and 

 remained as pupae throughout the winter. Privet was used to feed the 

 larvae after the lilac leaves had all fallen. 



Very few records are to be found giving any useful information con- 

 cerning the genetics of this melanic variety. Pearce^ and Southey^ both 

 bred the melanic form, but their records are too deficient to be of much 

 value. The most detailed experiments are those of Hamling and Harris 

 already mentioned. Their data have been summarised by Tutt in British 

 Lepidoptera, Vol. v. but are very misleading, owing to no less than seven 

 errors, four of which concern the colour of the parents of the families 

 recorded. The following tables have been compiled from the original 

 records of Harris, and of Hamling. 



Type X Type. 



Imagines 



Melanic Type 



Bred by Male Female Totals Male Female Totali 



T. H. Hamling (1904) — 1 1 12 6 18 



E. Harris (1905) ... — — — 9 9 18 



H. Onslow (1919) ... — - — 3 — 3 



Totals 1 39 



1 Pearce, W. G., Ent. Rec. Vol. x. p. 121, 1898. 



2 Southey, W. A., Ent. Rec. Vol. x. p. 122, 1898. 



