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JOURNAL OF VARIATION. 



No. 8. Vol. II, September 15th, 1891. 



THE GENUS ACRONYCTA AND ITS ALLIES. 



By Dr. T. A. CHAPMAN. 



[Coiitintied from page 131.) 



\CRONYCTA {Cuspidia) uiegacephala. — This species 

 is most nearly allied to alni in one very important 

 respect, viz., the distribution of the dark and pale 

 segments of the newly-hatched larva. It also 

 resembles it in the less important matter of living as a larva 

 on the middle of the upper surface of a leaf It presents an 

 approach to leporina and aceris in the tubercles and their hairs 

 becoming less marked as the larva gets older, in the surface 

 hairs being very obvious, though very minute, and in the in- 

 creased number of spines carried by the pupa. The resem- 

 blance of the perfect insect to rumicis or auricoina, has, I 

 think, been attained independently, as an instance, of allied 

 species finding it possible and profitable to assume a similar 

 facies ; or to express it differently, in tracing both back to a 

 common ancestor, we should somewhere come across a form 

 unlike the existing one, and more like, perhaps, tridens. 



The egg is the largest of any, being i'23 mm. in diameter ; 

 it is also a good deal flatter than any others. It is laid 

 solitarily, but as the moth, when laying, is rather inclined to 

 buzz about than to fly far, eggs are probably laid on neighbour- 

 ing leaves (on the upper surface ?) more often than with other 

 species ; when first laid it is of a pale greenish colour, uniform 

 throughout, and when the dark dots first appear, the inner egg 

 has not begun to shrink from the margin. When fully matured 

 in colour, the colourless margin, due to the shrinking of the 

 inner egg, is wider than in any other species and has the 

 appearance of a frill round the egg proper, this great width is 



