254 THE ENTOMOLOGIST. 



margin of the anterior segment and the borders of the 

 spiracles yellowish. The thoracic legs were yellow, with 

 brown claws, and had a black mark on the last joint. The 

 folds at the side were slightly hirsute. There were six pairs 

 of abdominal legs, yellow, with a small transverse black line 

 on the outside. The anal valve was brownish black, having 

 a small spine on either side (fig. 4). Lastly, the ventral 

 surface of the last segment and the two anal legs were deep 

 yellow. These larvae, which fed on the birch, were of a 

 restless nature, frequently raising the abdomen and curving it 

 over the back, in which position they would remain for some 

 time. Hardly had the colony returned to a state of rest, and 

 each individual assumed a natural position, when one of the 

 number became restless, and commenced waving about from 

 side to side, its example being followed by all the others, and 

 some time elapsed before there was another pause. In their 

 restless habit, as well as in their gregarious mode of living, 

 they more nearly resembled Septentrionalis than Varus. On 

 the apodal 4th segment, and on the 5th and 6th, between the 

 legs, were greenish gray dermal processes, which could be 

 reverted like the horns of the snail : these organs (fig. 5), which 

 could be protruded to three times the length of the legs, were 

 open at the extremity, whence a viscid and fetid fluid could 

 be ejected. We have already observed similar glandular 

 openings in nearly allied species. 



In the beginning of October the larvae took to the earth, 

 and buried themselves as deeply as they could in the jar : the 

 cocoon, which was single, was black and tough, very smooth 

 within, and rough exteriorly, and curled up ; in these the 

 larvae passed the winter. They passed into the pupa state at 

 the end of April, being probably at first white and afterwards 

 coloured. On the 5th of May of this year I found one which 

 had already acquired its full colouring ; of this I made a 

 drawing (fig. 7), which calls for no special remark, excepting 

 that the insect in question had so nearly reached the time for 

 shedding the thin pupal membrane that the antennae were no 

 longer lying along in front of or between the legs, but were 

 being moved about ; in fact, the first imago, a female, 

 appeared on the 4th of May, and was soon followed by 

 others ; a male appeared later. The female (fig. 8) had the 

 head, thorax and antennae black ; palpi gray ; cenchri white ; 



