258 THE CANADIAN ENTOMOLOGIST. 



two species. The first specimen to emerge, a male, proved to be an 

 almost exact counterpart of the right-hand side of Drury's figure of 

 phyllira (both sides are not similar), and we had no hesitation in identi- 

 fying it as such. Compared with our first species, we could note follow- 

 ing differences : (i) in species No. i the medial band of primaries is 

 distinctly outwardly oblique, being much closer to the postmedial band 

 on the inner margin than on the costal edge ; m phyllira the two bands, 

 when present (the medial band is often absent), are practically parallel ; 

 (2) in species No. i the underside of abdomen and the anal tuft are 

 entirely black, \n phyllira the anal tuft is bordered with cream and the 

 underside is creamy, with two rows of black dots. Using these differ- 

 ences as a basis of separation, we examined the series of specimens 

 already in the collection of Dr. Barnes under the name of phyllira and 

 were able to separate out a series of each ; of phyllira both males and 

 females were represented ; of our species No. i, however, we noted that 

 only males were forthcoming, when, in addition, a survey of the series of 

 placentia brought to light the fact that it consisted entirely of females, we 

 began to "smell a rat" and remember that such a factor as sexual 

 dimorphism must always be reckoned with. In neither of the latest 

 works on the subject (Neumoegen & Dyar Revision of Bombycid Moths, 

 Hampson Cat. Lep. Phal., Ill), could we obtain any information ; both 

 authors dtscx'ihQ placejitia according to Abbott's figure ; in fact Hampson 

 seems to have confused the two males under the name phyllira, for he 

 notes under this species that the abdomen is black beneath, a statement 

 that does ?iot hold for the true species. At last, in Stretch's plates of 

 Arctiidse, recently published in the Jour. N. Y. Ent. Society, we came 

 across a figure oi^ placentia male, which exactly agreed with our species 

 No. I ; others before ourselves had evidently arrived at the same conclu- 

 sion ; as, however, no text had been published to the figures, we were 

 unable to determine whether the grounds for such a conclusion were 

 sufticient ; a few days later a freshly emerged typical i^vadX^ placentia in 

 our breeding cage removed the last remnants of doubt we may have had, 

 and proved conclusively that placentia shows a marked sexual difference. 

 How far this fact is generally known we are unable to determine ; we 

 know, however, of no published statement concerning this variation, and 

 trust that our remarks on the subject will not be entirely without interest. 

 A reference to the accompanying plate will show more clearly than we 

 can explain the points of similarity and difference between the species. 

 We have been successful in obtaining two pairings of ^. phyllira and the 



