XYLENA. 25 



but from the fifth to the eleventh segments they are arranged 

 in a trapeziform manner, the two anterior ones being always 

 the largest ; and on the twelfth segment are four larger tubercles 

 arranged in a square. There is a black spot on the last 

 segment, which is lost in the anal fold. The sides are also 

 set with a number of tubercles. The legs are ringed with 

 black, and each of the pro-legs bears a black spot. The trans- 

 formations take place in the interior of the stem. The pupa 

 is elongated, and reddish-brown in colour. The moth appears 

 after three or four weeks, in August or September. 



GENUS XYLENA. 



Xykna, Hiibner, Tentamen, p. i (18 10?); Ochsenheimer, 



Schmett. Eur. iv. p. 85 (18 16). 

 Xylina, pt. Treitschke, Schmett. Eur. v. (3), p. 3 (1826); 



but not of later authors. 

 Xylophasia, Stephens, 111. Brit. Ent. Haust. ii. p. 174 (1829); 



Guenee, Spec. Gen. Lepid. Noct. i. p. 135 (1852). 



This genus includes comparatively large species, with long 

 and rather broad sub-triangular wings, with the hind margins 

 slightly denticulated ; the antennae long, slightly pubescent or 

 ciliated in the male ; the thorax slightly crested in front, and 

 the abdomen long, rather stout, and crested. There is an 

 apical tuft in both sexes, and large lateral tufts before the tip 

 in the male. The light W formed by the sub-terminal line on 

 the fore-wings is well marked in many of the species. 



The larvee are stout, shining, cylindrical, with small warty 

 elevations ; they are generally found at the roots of plants, or 

 under stones. The pupa is enclosed in a brittle earthy 

 cocoon. 



I have figured the type of this genus. One of the commonest 

 British and European Nodufz is the Dark Arches {X. polyodon, 



