XLIX 



The eye-spots, which I term true ocelli, are characterized, as has been 

 stated, by various concentric colour rings and, as Bateson correctly observes, 

 strongly suggesting the notion " that the whole series of rings may have been 

 formed by some one central disturbance, somewhat as a series of concentric 

 waves may be found by the splash of a stone thrown into a pool ". Now 

 the production of colour rings round an excisting centre is not entirely unknown 

 in Lepidoptera. In my paper Over dc o?ihvikke/i>ig van eenige Javaansche Papi- 

 lionidenrupscn published in 1888 in volume XXXI of the Tijdsehrilt voor Ento- 

 mologie I showed, for instance, how in the caterpillars of Papilio Agamemnon L. 

 and P. EuRYPYLUs L. (Jason Esp.) a ring of coloured pigment is formed 

 round the base of the spines on the third thoracical segment ; a similar ring 

 spot is also found in the larva of Ptehogon Oenotherae Esp. round the horny 

 last vestige of the horn peculiar to the caterpillars of Sphingidae. It appears, 

 therefore, that where on the body surface a certain induration occurs inter- 

 rupting or disturbing the normal distribution of the pigment a ring-shaped 

 accumulation of the latter round the obstruction results. This, moreover, 

 apparently occurs not only in caterpillars ; the origin of the 8 shaped figure 

 on the under side of the hind-wings in Callidryas Scylla L. and C. Pomona F. 

 I considered, when treating of the }ava Pieridae, could only be accounted for 

 in this way, /. c. by assuming that in certain places of the wings small indu- 

 rations — probably traceable anatomically — are formed, around which the 

 pigment present begins to accumulate in ringshaped fashion. The same or 

 something similar, it may be assumed, causes the production of the ocelli in 

 the wings of butterflies and a knowledge of the process of colour evolution 

 strongly supports this assumption. It is, indeed, by no means impossible that 

 in some genera or species certain anatomical impediments against the normal 

 distribution of the pigment, as this occurs under the stress of the process of 

 colour evolution, operate in specific places on the surface of the wings, 

 corresponding to the above mentioned indurations to that extent. The fact 

 noted by Bateson that in Satyridae the ocelli occur invariably on one of the 

 creases or fold marks of the wings between two nerures, /. e. just, therefore, 

 where such a disturbance would take place, deserves consideration in this 

 connection, as well as the observation by the same author that such ocelli on 

 the upper and under sides of the wings, indeed, sometimes occur which completely 

 coincide but that this is by no means always the case and consequently the 

 assumed disturbance may possibly occur in one of the two sides of the wings only 

 which, indeed, agrees entirely with the fact that the process of colour evolution 

 pursues its course independently with regard to either ot these surfaces. Some 

 other explanation in this connection may, however, present itself, /. c. that to 



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