dix. 531 



this caterpillar may show that in the case of smaller foes 

 the eye-spots are effective as a means of causing alarm. 

 The dimorphism of the larva of C. Capensis is of special 

 interest, although we are not yet sufficiently acquainted 

 with the habits of this species to offer a complete ex- 

 planation. According to Dr. Weismann's conclusions 

 (p. 297), the dimorphism of the C/uerocaw/>a-\arvx is due 

 to a double adaptation, the insects first having acquired 

 the habit of concealing themselves by day, and the dark 

 form having then been produced by the action of natural 

 selection, in order to adapt such varieties to the colour 

 of the soil, whilst others retained the green colour which 

 adapts them to the foliage of their food-plants. In 

 accordance with this, C. Capensis may have a similar 

 habit of concealment, or (should this be found not to be 

 the case) it is possible that this insect at a former period 

 possessed this habit and fed upon some other plant, when 

 it would have become dimorphic in the manner explained, 

 and the existing dimorphism may be a survival of the 

 more ancient dimorphism, the red form (corresponding 

 to the older dark form) having been subsequently modi- 

 fied so as to become also adapted to the new food-plant. 

 Much light would be thrown upon this by studying the 

 ontogeny of the species. 



Phytophagic Variability. A number of observations 

 . bearing on the phytophagic variability of the Sphinx- 

 larva; and other caterpillars have been recorded in a 

 previous note (p. 305), and reference has also been made 

 to the food-plants of Aclicrontia Atropos in South Africa 

 (note 50, p. 263). I am now enabled to add some 

 further observations on this species, from notes furnished 

 to me by Mr. Roland Trimen, who states that for many 

 years he has noticed that at the Cape this larva varies 

 greatly in the depth and shade of the green ground- 

 colour, the variability being in strict accordance with the 

 colour of the leaves of the particular plant on which the 



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