( 13:5 ) 



other segments together ; comb of midtarsus indicated by a few long bristles ; 

 paronychium with or without lowj; lobe (seasonal difference ?). Mesonotum and 

 occiinit grey or black, witli intergradations, iij)per half of mesothoracic tegnla also 

 grey or black, with a rather indistinct blackish middle line. Forewiag : a black 

 line npon R', entering cell ; the white baud at the distal side of the weak black 

 snbmarginal line much broader than in chcvsis. 



i. Tenth abdominal tergite gradnally narrower to end, which is abruptly 

 jMiiuted, gradually curved, snbcylindrical, being convex above and somewhat less 

 so below ; sternite short, broad, not sinuate mesially, the sides turned upwards 

 (PI. XXVIII. f. 12, side-view; f. 13, dorsal view). Clasper as in chersis ; harpe 

 (PI. XXXVIII. f. 6) very different from that of all the other Ilijloicns, consisting 

 of a long, flat, tapering plate wliich terminates in a point ; its dorsal edge is 

 continuous with the subdorsal fold of the clasper, which fold bears very long 

 bristles ; its ventral edge is more or less irregularly sinuate and bears here and 

 there a small sharp tonth. Penis-sheath (PI. XXIX. f 5) not unlike that of 

 auicoin-erensis, but the jirocess longer, its ape.K slightly incrassate, rounded, almost 

 knob-like. 



?. Vaginal plate (PI. XX. f 18) with a very large cavity, into which opens 

 the vagina, the cavity extending to near the base of the plate : its roof is more or 

 less contracted in dry specimens, especially proximally, so that the opening is 

 not of the same size or of the same shape in different individuals ; the figure is 

 taken from a specimen in which the edges of the roof of the cavity approach each 

 other, the jilate bearing in this case an obvious resemblance to that of lanccolata ; 

 the plate differs from that of chersis not only in the much larger size of the cavity, 

 and the much more proximal position of the mouth of the vagina, but also in the 

 presence of a broad, ovate or elongate, mesial tubercle, homologous to the longer 

 and narrower mesial rounded keel of lanceolafa. 

 Larva and chrysalis not described. 



We unite here xwuXqy in'releydus two forms, one with grey, the other with black 

 mesonotum, the forms corresponding to those of //. vancouverensis, but differing 

 from one another not only in the colour of the thorax and wings, but also in the 

 structure of the claw-segment of the tarsi. The form with grey thorax is generally 

 considered identical with r/iersis chersis, or chersis oreodaphne, from which it is, 

 however, specifically distinct. Both forms of perelegans agree in the sexual 

 armature and in some essential characters of the wings, and from this we conclude 

 that the peculiar divergency in the development of the claw-segments does not 

 indicate sjiecific distinctness of the two, though we were very much surprised 

 when we discovered that we had here a case of apparently rpiite constant strn<'tural 

 dimorphism. The differences may be seasonal, but the dates of our specimens, as 

 in the case of vancouverensis, do not absolutely point to this ; breeding alone will 

 clear np the ijucstion. 



(■('. II. perdeydus f. aselliis nuv. (PI. XI II. f. 2, cJ). 



In collections confounded with //, chersis orMtliiphne. — Type: Colorado. 



cJ?. Occiput and mesonotum grey; ground colour of forewing also almost 

 uniformly grey, white snbmarginal band broad ; fringe with distinct white spots. 

 Puroiiychiuni reducod fPI. LXIV. f U. 1.')), without lobe. 



