190 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xii, 



The edge of the hind wings is yellow, but on the inner angle the fringe is whitish. Ocellus 

 not so long as wide (4£ by 5 mm.), with no traces of red scales either inside or outside of the 

 discal veins. 



The under side of both pairs of wings whitish, and the ocelli of both pairs of wings are 

 much smaller and paler than in the winter form, those of the hind wings being no larger than 

 those of the fore wings. 



Length of fore wings, 50 mm. 

 Breadth of fore wings, 31 mm. 

 Length of hind wing, 70 mm. 

 Breadth of hind wing, 33 mm. 

 Length of tail, 28 mm. 

 Breadth of tail, 7 mm. 

 In neither of the two forms are there any traces of an extradiscal line. 

 Climatic varieties or races. — While T. luna from Maine to Texas and Florida and through- 

 out the United States north of Mexico offers so far as yet known no local or geographic races, the 

 case appears to be different in Mexico and Central America. There, on the southern outskirts 

 of its range, it seems to have been affected by climatic agencies, and to have varied locally in 

 different directions and to have been differentiated into perhaps three local races or varieties, 

 i. e., T. luna var. 1, dictynna; 2, azteca; and 3 truncatipennis. 



(1) Tropaea dictynna Walker, Cat. Lep. Het. Br. Mus., VI, p. 1264, n. 8 (1855). 



Walker's description gives no locality for his specimen, which was contained in Mr. Saun- 

 ders's collection. He remarks: 



"This species much resembles T. luna, but may be distinguished by the band on the wings, 

 by the not empurpled exterior border, by the fore wings, which have a less oblique and more 

 straight exterior border, and by the hind wings, which have shorter tails." 



A 9 in the Oxford Museum, which agrees with Walker's description, was examined by 

 me, thanks to the courtesy of the attendant in charge. In this specimen the fore wings are 

 broad and obtuse at the apex; there is a pale greenish-brown distinct extradiscal line, situated 

 a little more than half way from the base to the aj)ex of the fore wings, being nearer the outer 

 edge of the wing than to the ocellus, and the line reappears on the hind wing. 1 The ocelli are 

 quite as in T. luna and those of the fore wings are nearly separated from then - stalk. The 

 edge of the wings is ochreous yellow. The tails are longer than in T. luna (Walker says the 

 tails are shorter). The hind wings are a little scalloped. The impression made upon me was 

 that this form is not distinct from T. luna. I also examined with more care and deliberation 

 the 3 , labelled T. dictynna in the British Museum, from Orizaba, Mexico, "at or near the 

 volcano," with the following results: 



It differs from four a* and five 9 of T. luna, in the same drawer, in the distinct extradiscal 

 brown band, which is wide and crosses the fore wings, not quite reaching either the costa or 

 the hind edge. The shape of the wings and the length of the tails as in T. luna. Outer edge 

 of both wings yellow and pale brown, as in T. luna. In the hind wings the outer edge is not 

 so much scalloped as in most of the examples of T. luna. The wings are ochreous green, rather 

 more so than in the examples of T. luna, and the squamation is rougher. Ocellus of the fore 

 wing as in T. luna, but there is less white next to the vitreous center, but more red, otherwise 

 the shape and coloration of the ocellus is the same. In the ocellus of the hind wings the yellow 

 ring is deeper ochreous than in some T. luna, but of the same hue as in some others; the red 

 ring is distinct. The ocelli in fact show no varietal differences. The moth is not quite so 

 large as the largest T. luna. 



At the time of examination I concluded that T. dictynna is hardly a climatic variety of 

 luna. 



That dictynna is only a banded form of luna, and liable to occur anywhere, is probable 

 from the fact that the late Mr. S. L. Elliot has bred it in Brooklyn on the walnut, having raised 



1 Mr. W. L. W. Field informs me that in examples bred by him at Milton, Mass., the bands appear after emergence from the coeoon as soon as 

 the wings expand, but that after about one hour they disappear. 



