THE YOUNG NATURALIST. 



[November 



pointed out the remarkable fact that " dichrodactylus only occurs on 

 Tanacetum, although Achillea may be plentiful in the same district,"" 

 that " there is a great difference in the tone of colour," that " when 

 specimens of bertrami have very falcate wings they are females only 

 and not of both sexes," that " the hollowed outer margin below the 

 apex is of a different shade in the two species," that " the palpi are 

 longer in dichrodactylus than in bertrami," and that " the spot at the 

 end of the fissure of anterior wings is fainter in bertrami than in dichro- 

 dactylus" " Entomological Monthly Magazine," Vol. XVIII., pp. 143- 

 144. After these practical notes, Mr. C. G. Barrett took up the 

 matter (" Entomologist's Monthly Magazine," Vol. XVIII. , p. 177. 

 I must now confess that I do not understand the use of Mr. Barrett's 

 brackets and " = " in the synonymy of the second paragraph, although 

 the paragraph itself is clear enough. In the then (and present) condi- 

 tion of our knowledge, he took up what appears to me to be the only 

 reasonable view of the matter that could be taken, sinking dichro- 

 dactylus, Miihlig, as a synonym of ochrodactyla, Hb., and the ochrodactylus 

 of Stainton and other authors as a synonym of bertrami, Rossler. He 

 then points out that bertrami feeds on Achillea in a very different way 

 to that which ochrodactyla feeds on Tanacetum, and concludes : — " The 

 habits of the larvae seem certainly to point to the distinctness of these 

 two species." In the " Entomologist's Monthly Magazine," Vol. 

 XXII., pp. 104-105, Mr. Porritt, after describing the larva of bertrami, 

 adds: — "It will be noticed from Mr. Buckler's description of the 

 larva of P. dichrodactylus ("Entomologist's Monthly Magazine," Vol. 

 XII., 233) that both species correspond in having three forms of 

 colouring in the different stages of growth, and the resemblance of 

 the adult larvae particularly, shows the close relationship of the two 

 species ; whilst the differences, apart from the food-plants, are 

 sufficiently wide to separate them." 



Nothing more of importance seems to have been found out, but 

 Mr. South received three larvae of bertrami in June, 1885, from which he 

 bred one imago, July 21st, 1885, and on these slender data Mr. South 

 re-opened the whole question of " two " or " one " species ; but as all 

 the arguments adduced had been previously used, and there was no 



* Mr. Porritt, "Entomologist's Monthly Magazine," Vol. XXIII., p. 163, dwells 

 very strongly on this point. He writes : — " In the Saltburn ravine, and also all 

 over the district, yarrow was in full bloom, and in equal luxuriance with the tansy, 

 yet not a single specimen of dichrodactylus was ever seen frequenting it, or any plant 

 but tansy. Bertrami evidently does not occur in the district at all, or we think we 

 must have seen it during our fortnight's stay." 



