1S88.] 117 



thci'e are five ii-regular white lines, which unite together in front, in the direction of 

 the head. The spiracles are white and small, except tlie last, which is conspicuously 

 larger than the rest. But the most striking feature of this larva is its wonderful 

 power of extending and withdrawing the first three or four segments of its body, 

 and reminding one of the larva of Choerocampa Elpenor, or of the common earth- 

 worm. When full-fed, the larvse spun a flat oval pad of white silk on the side of 

 tlie musliu bag in which they were reared, and thereon remained for twenty-four 

 hours or longer, perfectly motionless, in a horse-shoe-shaped form, the head in close 

 proximity to the tail. After this interval of rest, they proceeded to spin the rest of 

 their cocoons, which were soon completed, being thin and transparent enough to 

 allow of the easy observation of every movement of the larva inside. The cocoon, 

 ■when finished, is oval, with the longer axis perpendicular, and the larvse all pupated 

 ■with the head upwards. They took a week to pupate, after the cocoons were com- 

 pleted ; and remained in pupa just a fortnight, the ? in all cases emerging twenty- 

 four hours sooner than the <? . The pupa of orichalcea may be at once distinguished 

 from that of gamma, which is wholly black, by its having the underneath part and 

 the wing-cases of a lovely pale green, a colour which, three or four days before 

 the perfect insects emerge, gradually changes into a dull pink, foreshadowing the 

 colouring of the under-side of the abdomen and wings of the imago. 



The habit of the larva appears to be to eat the young top-leaves of the Eiipa- 

 torium, and work downwards. When not engaged in feeding, it rests on the under- 

 side of a leaf, grasping the midrib. 



One larva, in the course of its last moidfc, failed to throw off its old skin in its 

 entirety : a narrow band of which remained in an oblique position, embracing the 

 eighth segment, the hinder part of the seventh segment on one side, and the former 

 part of the ninth on the other. This band, as it dried, had tightened, constricting 

 the body, till it was only half its normal diameter, and enabling the whole of the 

 internal structure and workings to be plainly seen. As the larva was evidently un- 

 able to extricate itself, I carefully inserted the eye of a needle beneath the ligature, 

 and, aided by sundry energetic wrigglings of the larva itself, split it asunder. The 

 body soon resumed its usual dimensions, and the larva fed up and turned all right, 

 and the imago emerged apparently perfect : but when I got it on the board, I found 

 the left fore-wing, though not ci-ippled, about one-eighth of an inch shorter than 

 the right. 



I think it is quite possible that Plusia orichalcea may be more widely spread 

 than is generally supposed. The perfect insect is rarely seen, except at night ; and 

 tlie larva would be easily passed over as only PI. gamma. I hope to be able to give 

 a fuller account of its earlier stages another year. 



I take this opportunity of correcting a slight error in Mr. Buckler's account of 

 the larva of Banlcia argentida in last month's Magazine, for which I am sure he is 

 not responsible. Mr. Raynor was not the rediscoverer of that insect. I had taken 

 some half-dozen, and Mr. Cross a couple, before Mr. Raynor arrived on the scene of 

 action, and his delight at our capture was unbounded. Moreover, the insect has 

 occurred in small numbers in Wickeu Fen more than once during the last ten or 

 twelve years. — W. Waeeen, Merton Cottage, Cambridge : September 17th, 1883. 



