TRIFID.-E. 235 



The infant larva has the head black, the general colour 

 rufous except the third, fourth, and eleventh segments, which 

 are very pale ; the spots are large raised bosses, paler than 

 the rest of the segment, but without very defined margins. 

 Each has one hair, dark at the base, pale at the tip, and of 

 one half the length of the larva ; second segment with a pale 

 plate ; the sides are paler than the back, the eleventh segment 

 is peculiarly wide and flat and its hairs paler than the rest. 

 As it grows it becomes more flattened from the tenth to the 

 thirteenth segments, and a dorsal lozenge of bright yellow 

 appears on each of the pale segments. After the third 

 change of skin some approach is made to the appearance of 

 the full-grown larva ; sometimes a yellow patch appears on 

 the back of many of the segments, and the raised spots 

 partially change colour to yellow, with some brown or black. 

 As it grows all the spots become yellow, the dorsal region 

 blackish, changing on the sides to very light fuscous, and 

 dotted closely with small yellowish or greenish-white points, 

 each carrying a minute hair, thus forming a fine pubescence 

 covei'ing the larva ; by this time the tubercular hairs have 

 become proportionately shorter, and the adult appearance is 

 gradually assumed. (Condensed from Dr. Chapman.) 



August and September on poplar and aspen, also rarely on 

 sallow. It reposes on the upper side of a leaf and lies always 

 in a curve or bend, with the head placed near or against its 

 side. Feeds by day and is quite easily seen. 



Pupa cylindrical, with tapering abdominal segments of the 

 usual form. Smooth and shining, limb cases not very distinct ; 

 reddish, with the dorsal region darker; anal tip rounded, 

 black, with a number of curved and hooked spines. In a 

 strong compact cocoon of dark silk mixed with morsels of 

 wood ; under bark or in a chink or crevice, or even in a hole 

 bored into rotten wood. In this condition through the 

 winter, sometimes through a second winter. Dr. Chapman 

 has even found one-half the pupa3 of a brood to lie over. 



