no. i. BOMBYCINE MOTHS OF NORTH AMERICA— PACKARD. 189 



Legs of a rich reddish brown ; the hair-like scales on the outside white. Abdomen and thorax 

 white, in some specimens tinged with yellow. 



Expanse of the fore wings, c? 81-12S mm.; length of wing, S 42-60 mm. 



Expanse of the fore wings, 9 80-140 mm.; length of wing, 9 41-65 mm. 

 Mr. W. L. W. Field informs me of the very interesting fact that directly after emergence 

 examples of T. luna reared in Milton, Mass., as soon as the wings are expanded after emergence 

 from the pupa have at first distinct extradiscal lines, which disappear within an hour. The 

 phylogenetical bearings of this phenomenon will be noted in another place. 



Variations. — Besides the ordinary or normal pale pea-green color, others are whitish. 1 One 

 9 from Louisiana is whitish green with wide and deep pink borders; one <? from Florida has a 

 reddish border, which, however, is much paler and narrower than in the Louisiana example. 

 Of six specimens bred by Mr. II. L. Clark in Rhode Island, two are whitish green in hue and four 

 are yellowish green. There seems to be a tendency in the New England individuals to have 

 yellow borders, and to be paler throughout; Maine ones are paler than more southern ones. 

 Specimens raised in Texas in 1870 differ from New England examples by the broad reddish pink 

 border of both wings, by the larger ocelli, while the markings are more distinct, the ocelli of the 

 fore wings being more distinct, especially on the outer edge. These notes were written during 

 an examination of the collection in the Cambridge Museum. 



Seasonal dimorphism. — As is well known, some individuals have a reddish and others yellow 

 edges and fringes to the wings. Mr. L. H. Joutel has explained to me the cause of this, i. e., that 

 the pinkish-red bordered individuals are the winter form, and the yellow-edged ones the summer 

 form. This of course applies only to regions where T. luna is double-brooded. In northern 

 New England we should expect, as there is but a single brood, the moths emerging in the early 

 summer from pupae which have wintered over, that the effect of cold on the wings would be to 

 produce red borders, and not yellow. The difference between the winter and summer forms 

 may be brought out by descriptions of two males, one a winter and the other a summer male, 

 kindly given me by Mr. L. II. Joutel, who informs me that they were bred at about the same time 

 (i. e., year) and fed on hickory leaves. From one cocoon of the lot that yielded the individual 

 of the summer brood here described the moth emerged a year after the others. The male of the 

 winter brood has decidedly falcate fore wings and is pea green, but with no yellow shade; the 

 middle of the outer edge of the fore wing is pink red, but on the apical region and along the inner 

 angle the red is replaced as usual by yellow. The ocellus is round and rather large (4 by 4£ mm. 

 wide) ; the stalk is well developed. 



The hind wings are unusually scalloped, the hinge yellow on the scalloped or anterior portion, 

 the edge behind red, this hue extending along the outer edge of the base of the tail. The apex 

 of the hind wings is unusually sharp. The tails are very long and narrow. Ocellus of hind 

 wings a little larger (4 A- by 5 mm.) than on the fore wings, and round. 



Length of fore wing, 50 mm. 



Breadth of fore wing, 27 '\ mm. 



Length of hind wing, 70 mm. 



Breadth of hind wing, 32 mm. 



Length of tail, 38 mm. 



Breadth of tail, 5 mm. 

 The male of the summer brood (which emerged a year after birth) has broad scarcely 

 falcate wings, thus assuming the shape of the 9 . The apex of the hind wings is very slightly 

 scalloped, and the tails are unusually short and broad. The wings are pale green, almost 

 frosted over with white, and the ocelli and costal bands are paler than in the winter form. 

 The ocellus of the fore wing is much smaller (3 by 4 J mm.) than in the winter form, with no 

 red semicircle on the outer edge of the white crescent (as there is in the winter form). The 

 discal end of the stalk is partly obsolete, the ocellus tending to be partly free from the stem. 



> [I noted in the U. S. National Museum that yellow-green specimens were males, light bluish green females. Dr. W. T. M. Forbes assures 

 me that this is a regular sexual difference.] 



