324 THE entomologist's record. 



follows : — " A batch of larvas of Vanessa antiopa which were 

 under-fed, produced seven dark specimens of small size, about 

 two inches in expanse" {in litt.)\ whilst of Melitcca cinxia he 

 writes: — " A few small bred specimens have the black mark- 

 ings (especially beneath) more pronounced." Dr. Buchanan 

 White {Ent. Mo. Mag., vol. xiii., p. 149) writes : — " Frequently, 

 melanochroic (and more frequently melanic) individuals are of 

 smaller size than the typical form." The influence that this (dis- 

 ease) must undoubtedly have, in experiments which we carry 

 out by breeding insects, must not be lost sight of altogether 

 in the inferences and deductions we may make from the 

 results apparently produced. 



In connection with disease as a cause of partial melanism, 

 Mr. Cockerell, writing under the title of " Suppression of light 

 markings," sa^^s : — " Papilio astenas var. astci'oides, Reak., 

 Liinenitis artheniis dimorphic forms lamina, Fab. and proser- 

 pina, Edw., Apatura iris var. iole, Schiff., Newman's British 

 Bntterjiies, 72, Mamestra persicarics var. unicolor, Stdgr. 

 These must, I suppose, be regarded as cases of partial 

 melanism ; but Mr. H. Goss {Entom. xi., 73), in describing a 

 dark variety of Chelonia villica from Brighton, mentions that 

 several dozen larvae from the same place produced the type, 

 and suggests further that the aberration was due to a diseased 

 condition in the larva. Now this variety exhibited coalescence 

 of the dark markings and suppression of the light ones, which 

 further, was more complete on the right than on the left side, 

 so it seems certain that it had nothing in relation with such 

 cases of melanism as Pieris napi var. bryonice. I am therefore 

 inclined to separate all dark forms into two groups : — (i). True 

 melanisms. (2). Cases of coalescence of markings due to 

 disease. What the precise nature of the disease may be, and 

 which forms precisely are to be classed in either group, is for 

 future investigations to decide " {Entomologist, vol. xxii., pp. 

 98, 99). I have in my cabinet three specimens of Vanessa 

 urticcB, bred by my friend Mr. H. Page, which were supposed 

 to have been crowded as larvae, which produced among other 

 slightly aberrant forms, two specimens with very suffused, and 

 one with perfectly black hindwings. Here there seems to be 

 some distinct connection between cause and effect. 



I have previously referred to the possibility of Mr. Merri- 

 field's results having been influenced, in the case of Selenia 

 ilbistraria, by a tendency to disease (possibly through inter- 

 breeding). How probable this is, may be seen by carefully 



