276 



THE entomologist's RECORD. 



resemble them so strongly, that I am certain I could not separate them 

 if mixed up. It is, however, worthy of remark, that I have never met 

 with the lighter forms of riissata during autumn, although the darker 

 ones seem pretty numerous, flying in a wood, close to the ground over 

 low flowers. — Hope Alderson. J^une, 1890. 



I have been repeatedly asked, during the season, for some good 

 character by which to distinguish these two species, and, although I was 

 well aware that there is not the slightest doubt of their specific 

 distinctness, I failed to satisfy any one, and was decidedly bothered, 

 when I tried to pick out iiJimanata from ritssata among those in my 

 possession. I have some hundreds of both species, and, after an hour or 

 two's study of the question, I think I can point to a character which 

 will readily separate them. I recollect, in 1884, calHng on Mr. Sydney 

 Webb; and, in the course of looking through his unrivalled collection of 

 varieties, the question of a character to separate the two was discussed, 

 when he pointed out to me what appeared to him to be a very 

 satisfactory one, viz., that in imma?iata, the edge of the dark band near 

 the apex of the wing runs from the costa in a bold curve before forming 

 the two teeth generally common to both, while in riissata, it slopes 

 gradually downwards as a more or less serrated line. This is a fair 

 character and will be useful in many cases, but, unfortunately, it is not 

 constant. I have undoubted russata with the immatiata character in 

 the band and vice versa, so I was reluctantly compelled to give this up 

 and seek further for something more decisive. I was decidedly at fault 

 at first, for anything is sent out from the northern counties and from 

 Scotland as imfuanaia, but, luckily, I had about a hundred russata bred 

 by myself, and some undoubted bred immanata, so at any rate I was 

 sure of some trustworthy material to work on. I find, on examination 

 of these specimens, that on the underside of the under wing is a more 

 or less conspicuous band or line, and that this band is constant in its 

 variations in the two species. Starting from the costa, about two-thirds of 

 the distance from the base, it proceeds downwards in a series of curves or 

 zigzags from nervure to nervure ; these are most pronounced in russata 

 (fig. 1). Reaching the first branch of the median nervure the band is 

 bent in immanata (fig. 2) almost at a right angle, and is continued nearly 

 parallel to the edge of the wing, until it reaches the hind margin, but, 

 immediately before this, it makes a sharp curve downwards. The band 

 in russata is not angled in the same way, but proceeds from the median 

 nervure in a bold curve, till it ends at the inner margin similarly to z>«- 

 manata. The band is often indistinct, sometimes obsolete, on the upper 

 surface of the wing, but it is very distinct in nearly every case on the 

 underside. There is a dark shade which follows the course of the band 



