THE CANADIAN ENTOMOLOGIST. 165 



NOTES ON CERTAIN VARIATIONS OF SAMIA CECROPIA. 



BY C. E. WORTHINGTON, CHICAGO, ILL. 



The deceptive effect of the variable border on the apparent shape of 

 the primary wings in Samia cecropia appears to have escaped general 

 notice ; indeed, in contrasting this species with £. promethea, the latter 

 is universally mentioned as having the primaries much broader in propor- 

 tion to the length. This is perhaps true of the average cecropia, but in 

 numerous individuals I have found primaries even broader in proportion 

 than in S. promethea $ , and narrower than in promethea £ , both by 

 traced outlines and shadow projections, in several instances those with a 

 wide light border appearing extremely narrow but proving to be even 

 broader than the average. 



This effect also extends to the so-called sexual difference in the wings, 

 the margin usually being broader and lighter and the apical patch more 

 brilliant in the males. 



A careful comparison of a considerable number of specimens shows 

 that no reliance can be placed on the breadth as a sexual character, and 

 that even the antennae (especially of those fed on Negwido fraxifolium) 

 sometimes approach so nearly as to be barely distinguishable. 



There are strongly marked variations in the apical patch outside of the 

 ^ line, generally indicated by a purplish reflection, but sometimes 

 brighter; occasionally above, and more frequently below, being a dull red 

 or a brilliant crimson ; more rarely over-running the line inwardly ; the 

 four black spots immediately inside of the zigzag line are often reduced 

 to two, those nearest the apex being obsolete. 



The discal spots vary greatly in color ; normally dull red with a white 

 centre, they are sometimes entirely red with no trace of white ; in others 

 they will be found almost white with merely a shade of red or pale brown 

 about the margin, and at the sharp end, where color is always present, 

 their shape varies from that of a pear to a long, curved (crescent-shaped) 

 line or a short straight mark, rarely so small as to be almost obsolete. 



Usually at the base of the primaries is a dull red spot, surrounded by 

 a black and white line, and at the base of secondaries a prominent white 

 patch extending along the upper margin ; in the first either black or white 

 may be wanting, while the latter, so far as regards the base of the wing, is 



