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in the direction we desire. On the emergence of the imagines 

 it would then be necessary to remove from the main breeding- 

 cage into an adjoining one all the specimens that did not 

 fall in line with what we required in the way of variation. Of 

 course, with species the sexes of which paired freely, it 

 would suffice to remove well-matched pairs into separate 

 cages, and in this way the object in view would probably be 

 more quickly attained. 



By eliminating varieties we do not want we are only acting 

 as nature herself would do in the production of a local form. 

 As a general rule it may be taken that the form of a species 

 which best harmonises with its surroundings is protected, 

 and as a consequence continues to flourish, whilst the less 

 favoured forms disappear. 



It should not be understood that the protective form is 

 entirely secure, for such is probably not the case. Neither 

 must it be supposed that the other forms all fall victims to 

 their enemies. By the action of heredity, or the law of 

 inheritance, varietal characters of the parent are transmitted 

 to the offspring ; it seems reasonable, therefore, to infer that 

 the protected form once having become dominant would, in 

 the course of time, become the only one. The means of 

 testing the validity of this inference is in your hands, and it 

 is to be hoped that some of you may be willing to take up 

 the matter. 



The larvse of some species of Heterocera vary almost or 

 quite as much as do the perfect insects, and this fact is 

 probably well known to every one who has collected larvae 

 of such species as Noctua /estiva and Boarmia repandata for 

 example, in any number. Probably individuals of the same 

 brood do not exhibit any considerable amount of difference 

 one from another ; but they may be very different from the 

 individuals of another brood, although both broods may 

 have been obtained from females taken in the same locality. 

 This is another matter that the rearer of Lepidoptera could 

 easily investigate, and it would add great interest to the 

 observation if comparisons were made between the larvae 

 at diiferent stages of their growth. 



Hybrids have been obtained by the experimental entomo- 

 logist, and it is quite possible that others will yet reward 

 further operations in this direction. Having decided on the 

 species for the experiment, it would perhaps be a good plan 

 to place pupas of each in separate cages, and let them stand 

 side by side. When the imagines appeared, the males of 

 each might be transferred, as soon as they emerge, from 



