{ XX ) 



desired to limit the term, and as he had ilhistrated it, no 

 such one-sided departure was manifest.* 



The President had called attention to the risk, in the case 

 of species of the same genus, or of nearly allied genera, of 

 mistaking for homoeochromatism a similarity due to blood- 

 relationship. Of course, the value of resemblances had to be 

 estimated in relation both to the range of form existing in 

 the genera or sections of a genus involved, and to disti-ibution ; 

 and the speaker did not admit that such a mistake had been 

 made in respect to any single species of his exhibit. As far 

 as his knowledge went, instances of non-mimetic homoeo- 

 chromatism among Neotropical butterflies were entirely 

 confined to the Neotropinffi, Heliconiins, and Hesperiidae, 

 although other subfamilies aflbrded mimetic forms. 



He had brought forward certain difficulties attending the 

 current theories ; Prof. Poulton's epicriticism thereon was 

 based largely on the assumption that each group possessed 

 some dominant form. The speaker had already pointed out 

 that the Miillerian theory was opposed to the existence of 

 dominant forms, and he knew of no direct evidence that such 

 actually were present — that was, species which could so far 

 influence a group as to compel its components to change 

 when they changed. His objections as to geographical 

 distribution had been met by two counter-suggestions, one of 

 which presupposed that a series of dominant forms had 

 preoccupied the country and had influenced the appearance 

 of the protected species which subsequently invaded it ; but 

 one could not bring oneself to believe without strong evidence 

 that the groups of insects concerned, the Heliconiinfe 

 and Neotropmae, were not coeval in distribution. Prof. 

 Poulton's comments on " hypertely " again presupposed the 



** Homoeochromatic pairs, such as those of Series I. in my 

 exhibit, are not demonstrably in the relation of " model " and 

 " mimic," but in one for which some other word must be found. 

 I would suggest that each member of such a pair, or group, which 

 does not show the departure indicative of a mimetic form, be 

 called the " homotype " of its associates. Thus HeUcanius galanthns 

 would be the homotype of, or homotypic with, H. luce. — W. F. 

 H. Blandford, Julij, 1897. 



