80 



THE ENTOMOLOCJISX S HECORD. 



space between the hindermost nervure, or second anal, of forewing, 

 and the dorsal margin is entirely red ; in eri/t/irus there is a little red 

 triangle at its base and the rest is dark ; in piirpuralia the base is 

 invariably dark, and a dark streak along the dorsal margin always 

 connects it with the outer-marginal band even when the anterior part 

 of that space is red along the nervure ; this character always allows 

 one to separate the three species, even in the very extensively red 

 specimens, which resemble each other most. Querci has found 

 rubicund IIS and jnnpiiralis together in the Sibillini Mts. and in the 

 Mainarde Mts., and cri/t/inis in a spot not far from them in the latter 

 locality. 



It is worthy of notice that the most extensively red Ziji^ana known, 

 rubiciindus, another of the most constantly red species, erythrus, and 

 the reddest European races of pinpuralis are proper to peninsular 

 Italy, that is to say to the very region in which most species of this 

 genus produce their most melanic races. It might appear at first 

 sight that the piirfniralis group reacts to the same surroundings in a 

 way exactly inverse to the more usual one. Further consideration 

 shows us that the same phenomenon occurs, on the contrary, through- 

 out the genus : the nervural pattern reaches its full extent in the 

 moist and colder climate of Central Europe, and tends to disappear in 

 the arid and warmer southern regions ; the primarj', true or transverse 

 pattern behaves exactly the other way, on broad lines. The result is 

 that piirpiiralis, which has no transverse pattern, is left with very little 

 dark marking in the south ; Z. camiolica, Scop., which has a very 

 limited capacity of developing a nervural pattern, is much more 

 broadly red in the northern region^ of its habitat and in the high 

 mountains of the south. I have pointed out that species like Z. 

 filifiendnlae, L., dealt with at length in a paper in these columns, in 

 which both the nervural and the transverse patterns exist together and 

 can both develop to a marked degree, produce their comparatively 

 reddest races in an intermediate zone and develop darker races, due to 

 the nervural pattern, to the north of this, and darker races, due co the 

 transverse pattern, to the south. A beautifully harmonious law of 

 variation thus unfolds itself before our eyes. 



Eaces of Z. rubicundus, Hb. 



This species may be said to be the least variable of the genus. Only 

 once has Querci found a remarkable individual variety of the male in 

 which the two cubital nervures of forewing were bordered with dark 

 scales, so that the dark naarginal band exhibited a projection towards 

 the cell, similar to the one usually seen in the form of pin-puralis, 

 known hitherto as pnlijiialae, Esp. ; to this form I have given the name 

 oi poliiiictlaeformU {Bull. Soc. Ent. Ital. xlvii. (1915), p. 71). In 1916 

 I suggested in the Bull. Soc. Knt. de France, p. 287, that some unujiual 

 looking specimens of Zi/i/aena collected by Kagusa at Palermo might 

 belong to a Sicilian race of nihiciiniliis resembling eii/fhnis much more 

 than the usual continental one; this assumption I based on the fore- 

 legs of the male, which are white ; I called this form eri/tJiraefonnis. 

 I must say however that I should like more materials to confirm this 

 hypothesis, because the specimens in question might very well only 

 be some weakly eri/thnis. The most northern locality known of 

 rnbicnndiis are the Sibillini Mts. (Piceno), where Querci has discovered 



