GEOMETERS. 



173 



thin silken cocoon in moss. I have now seen, 

 in all, about fifteen specimens of C. fluviata, 

 and six of C. gemmaria, and find that the 

 absence in each of what were considered the 

 distinctive markings of the other is not con- 

 stant ; the subapical blotch of C.fluviata may 

 be traced more or less distinctly (sometimes 

 quite distinctly) in C. gemmaria; while some 

 specimens of C. jhiviata have the central spot 

 placed in the light ring, only the dark ground 

 of C. gemmaria makes this ring shine forth 

 much more brightly, just as a negro's sable 

 skin enhances the whiteness of his eyes. One 

 of my bred specimens, having given me the 

 slip over the edge of the table, was detected 

 in a dark corner of the room by the white spots 

 on the fore wings. As to the other markings, 

 they are, line for line, precisely similar, so 

 that the ground colour alone remains to make 

 the sexes look unlike, and perhaps further 

 breeding may sometimes upset this." 



The MOTH occurs occasionally throughout 

 the summer, and there appears to be a succes- 

 sion of broods : it seems to be most common 

 in the vicinity of London, where it frequents 

 the gas lamps, but single specimens have been 

 taken at Lewes, Brighton, Bristol, Derby, and 

 Warrington, and Mr. Birchall informs us it 

 has occurred at Howth and Malahide, in Ire- 

 land. (The scientific name is Camptogramma 

 fluviata.} 



340. The Fern (Philalapteryx tersatd). 



340. THE FERN. The antennae of the male 

 have extremely short pectinations, giving 

 them the appearance of being stouter than 

 those of the female; the fore wings are 

 wainscot-brown, with various umber-brown 

 streaks and dots which are generally seated on 

 the wing-rays; a short oblique streak descends 

 from the tip towards the middle of the wing, 

 and there is a short transverse streak near the 

 base of its inner margin; there is also a zigzag 



whitish line parallel with the hind margin, 

 and terminating in a white spot near the anal 

 angle ; there is a very small brown discoidal 

 spot : the hind wings are paler than the fore 

 wings, with several darker waved lines on the 

 disk, and one zigzag white line near the hind 

 margin ; at the base of the wing is a short 

 transverse brown line : the body is wainscot- 

 brown, with a dark brown belt near the base ; 

 when the wings are spread out, this belt 

 unites with marks already described on the 

 fore and hind wings in forming a somewhat 

 crescentic ornamentation. 



The CATERPILLARS of this species are thus 

 described by Mr. Beauchamp : " During the 

 last week of August and the first fortnight 

 of September, 1861, 1 beat a number of these 

 caterpillars, in company with those of Mela- 

 nippe procellata, from the common clematis 

 (Clematis mtalba) after dark. They are long, 

 slender, and tapering towards the head, which 

 is small, flat, and rounded ; the ground colour 

 is very pale grayish-brown; the dorsal line is 

 dark brown, very conspicuous and broad on 

 the head, thence tapering to the end of the 

 fourth segment, where it generally becomes 

 invisible, re-appearing, however, as a gray 

 spot just behind the intersections of the seg- 

 ments, and on the tenth segment broadening 

 into a conspicuous black spot, which tapers to 

 a point forwards. Similar spots, but much 

 fainter, can be traced on the eighth and ninth 

 segments, and sometimes on the seventh. On 

 the hinder part of each of the middle segments 

 is a pair of spots of the same colours as the 

 gray spots before mentioned, with which they 

 form a triangle ; the spiracular line is slender, 

 pale, and edged on each side with dark ; the 

 sides below the spiracles are paler and rather 

 ochreous. The spots and spiracles are con- 

 spicuous, black, ringed with pale ; the ventral 

 line is pale, rather broad, and edged with a 

 dark line of considerable but variable breadth ; 

 there are numerous longitudinal lines, and on 

 many specimens transverse dorsal shades, 

 especially on the middle segments. In some 

 examples, all the above markings are very 

 indistinct, except the conspicuous black spot 

 on the tenth segment. 



