MIMETIC ASSOCIATIONS 



31 



difficult to understand how such a great modification can have been brought about, assuming 

 that the male represents the ancestral coloration. In this case we see, however, the com- 

 pleted condition without the intermediate varieties, and further acquaintance with mimetic 

 forms will disclose instances in which the progress of the development of the mimetic pattern 

 can be more easily traced. It should be borne in mind that we are not bound to suppose 

 that the insect which acts as a model should not at one time have borne characters 

 which enabled an easier approach on the part of the mimic. Further than this, we owe to 

 Dr. Dixey ^ the knowledge that a mimetic butterfly need not necessarily have begun its course 

 of mimetic modification in association with the species which now forms its model. This 

 author has shown how in certain cases amongst the Neotropical butterflies a very smaU 

 variation in the pattern of a butterfly may bring about a useful resemblance to some other 

 species. This change having been established, a further slight modification may cause 

 the insect to enter the sphere of attraction of some other dominant form, and this process 

 repeated may culminate in the ultimate form exhibiting very wide differences from its 

 ancestral type, differences which appear inexplicable when the intermediate and connecting 

 links have been removed. In the case of H. misippus, we are not, however, entirely without 

 knowledge of an intermediate form. The Oriental H. holina, the male of which is very 

 similar in appearance to H. misippus, has a form of female known as nerina, which shows 

 a reddish-brown suffusion of the wings which would appear to hint at the origin of the present 

 colour of the female H. misippus. The present typical form having been established, only 

 a small step is necessary to produce the remarkable variations shown on Plate II, Fig. 6, 

 which shows an example of the variety alcippoides. Here we have a white suffusion of the 

 hind- wings causing the insect to resemble the alcippus variety of chrysippus. Fig. 10 shows 

 the form inaria which is losing the black and white apical area in the fore-wings in corre- 

 spondence with chrysippus dorippus. Occasionally, as in Fig. 4, misippus is of an unusually 

 dark form, thus resembling still more closely the usually dark examples of its model in the 

 African region. The inaria form sometimes develops a tendency to albinism in the hind- wings 

 forming the variety dorippoides, Fig. 12, thus approaching chrysippus albinus, whilst 

 intermediate forms are occasionally found, such as that shown in Fig. 16. It is interesting 

 to note that from a female very similar in appearance to Fig. 16, Mr. Rogers at Rabai bred 

 fifty females of misippus, all of which were of the inaria form, the sole variation being 

 that some had a tendency to albinism in the hind-wing. It is one of these examples which 

 I have shown at Fig. 12 . 



As with D. chrysippus, the geographical range of H. misippus is exceedingly wide, in 

 fact it is actually found in regions where the former insect does not occur, as for instance 

 in Florida and in South America. The only Old World locality in which it does not, so far as 

 has been recorded, accompany its model, is on the European shore of the Mediterranean. 

 Dr. Longstaff found a single damaged example of the male of this species in the Khedivial 

 Agricultural Society's Museum at Cairo. The specimen had been taken in the district, n 

 an interesting fact which shows the extreme range of the species to extend further north 

 than is generally supposed. Collectors agree that the similarity between the two insects 

 when alive is such as to deceive even a practised eye. This is not to be wondered at when it 

 is known that even the male D. chrysippus is deceived. Trimen describes how he once 

 watched a male of the latter species pursue for a long time a female H. misippus, in the 

 belief that it was one of its own species. Dr. Longstaff also records (Trans. Ent. Soc, 1905, 



1 See Mimetic Attraction : Dixey, Trans. Ent. Soc, 1897, p. 317, &c. 



