294 THE entomologist's l^ECORD. 



not only give variations in colour (in the same brood), but slight 

 variations in markings as well ; in our breeding-cages the 

 variation is more pronounced. It is manifest here, that in this 

 species "heredity" would be a naturally strong factor, and, if 

 we add to the natural hereditary tendency to vary, the in- 

 creased hereditary iniluences produced by an artificial condi- 

 tion of life, and ,the result of possible interbreeding, we see 

 how potent a factor it might become. But this is not all. 

 This particular species (and there are many others similarly 

 inclined) has not only a natural tendency for the specimens of 

 each brood to vary inter se, but it exhibits strong dimorphic 

 coloration in its broods according to season, so much so, that 

 we talk of the dark spring brood and the paler summer one ; 

 and, although in nature, these colours are generally constant, 

 and even moderately so in our breeding-cages, yet, added to 

 the previous hereditary influences I have shown to be at work, 

 we see how strongly developed the sum total of heredity is, 

 and how useless for any purpose of exact experiment relating 

 to colour or markings, this species becomes. I have dealt 

 thus fully with this species because it not only exhibits the 

 hereditary tendency to a very full extent, but it is unfortunately 

 (probably because it is so hardy and easy to rear) the species 

 which has been generally selected for temperature experi- 

 ments.^ The other species, Ennoinos autiivmaria, which has been 

 used for experiment by Mr. Merrifield, is one which is much 

 better suited for experiment, as its natural tendency to vary is 

 less ; but being excessively rare in Britain, the species is being 

 interbred in vast numbers for our cabinets, and, in a few years, 

 will be quite domesticated, and probably become absolutely 

 useless for experimental purposes, as it is now (1889), more or 

 less, from my point of view, for it is impossible to get new 

 British stock except at very rare intervals. I think I have 

 now written enough to show that experiments made under 

 artificial conditions, are open to grave objection, and that we 

 may not always assume that results are produced by the same 

 forces in nature, as those by which similar results appear to be 

 produced under our artificial methods of breeding. 



The foregoing paragraph on heredity was written in the 

 early part of the year 1889, and my assumptions now (Jan., 

 1891) appear to be receiving most positive confirmation. In 

 the Report of the Meeting of the London Entomological 

 Society, Dec. 3rd, i8go {vide Ent. Record, vol. i., pp. 267 and 



^ It was unfortunately one of those selected by Mr. Merrifield. 



