220 



PSYCHE. 



[April 1895. 



Meadii is remarkable. Oinitting two 

 examples, the largest (50 mm.) and 

 the smallest (43 mm.), the remaining 

 forty show a variation in expanse of 

 only 4 mm., from 45 to 49 mm. In 

 I£lis, leaving out the lowest term (one 

 specimen of 40 mm.) ami the highest 

 term (two of 56 mm.), the pendulum 

 of variation still swings between 45 and 

 54 mm., a range more than double that 

 of Meadii. Hecla, also, is evidently 

 far more variable in expanse than 

 Meadii., as shown even by this small 

 series. 



A comparison of the shape of dark 

 border of fore-wing furnishes a valid 

 distinction, parting Hecla from El is 

 and even more emphatically from 

 Meadii., while it separates less deci- 

 sively Elis from Meadii. In a ver)' 

 large majority of the Meadii ^ the dark 

 border of fore-wing extends a consider- 

 able projection toward base of wing, 

 both at internal angle and at apex. 

 Owing to this salient projection the 

 fore-wing is rendered extremely broad 

 on costa. The curvature of inner edge 

 of border, however, is s?) great that the 

 costal excess of breadth is rapidly parted 

 with in the backward course of the 

 border. From a point of fore-wing 

 nearly opposite the cell-spot, to a point 

 a little l)ack of posterior median 

 nervule, the dark border of Meadii J 

 in a large majority of the specimens 

 examined maintains closely an equal 

 breadth This is plainly the case in 39 

 of the 43. In the other 3 the border 

 narrows very slightly from the front to 

 the back of this median part ; in one of 



them on both fore wings, in the other 

 two on right wing only. The rule 

 then in Meadii, and a rule of almost 

 universal application, is that the dark 

 border of fore-wing is disproportionately 

 broad on costa, loses this excess of 

 breadth anterior to a point nearly oppo- 

 site the discal spot, and throughout the 

 median portion of the wing maintains 

 closely an equal breadth. In a con- 

 siderable proportion of individuals the 

 border abruptly narrows more or less a 

 little anterior to the submedian nerve, 

 the disk color encroaching upon the 

 marginal border in a broad irregular 

 sinus whose deepest extension usually 

 occvus at the submedian nerve. 



The seven males of Hecla present a 

 radically differing pattern of fore-wing 

 border from that displayed by Meadii. 

 The excess of breadth at costa, instead 

 of being quickl}' dissipated in the back- 

 ward progress of the border (as in 

 Meadii') , is parted with very gradually 

 and evenly, so that Hecla' s dark border 

 becomes progressively narrower from 

 costa to internal angle. This general 

 method is plain in all the seven, though 

 ill two of them a part of the median 

 extent of the border shows but a slight 

 narrowing within itself. In all the 

 Seven a gradual reduction of breadth 

 from costa to internal angle is a sys- 

 tematic detail, and it would effectively 

 part them from all these JMcadii males 

 were there no other distinction. The 

 differing shape of the fore-wing dark 

 border is a far more decisive distinction 

 between the two species than is the 

 difference merely in breadth of border. 



