234 BRITISH LEPIDOPTERA. 



and redder (on the average). The front of H. euphorbiae is com- 

 paratively smooth and rounded, with no tendency to spines or tubercles. 

 The pupa of C. gallii may be about as smooth, but there are often 

 distinct frontal spines (epiclypeal) beside the labrum, and fainter 

 ones on the summit of the head. The summits of the wrinklings 

 (cerebral convolutions) vary in height, or appear to do so. and the pupa 

 feels rougher, apparently this is due to the wrinkles in the pupa of H. 

 euphorbiae having flat tops and very narrow perpendicular-sided valleys 

 between, whilst in that of C. gallii the valleys are wider and more open 

 and the ridges consequently narrower. On the abdominal segments, 

 pitting does not so soon or so completely replace wrinkling, so that, 

 on the 4th abdominal segment, it is doubtful whether it would be 

 easier to describe the sculpturing in terms of wrinkling or pitting. 

 In the described specimen of H. euphorbiae the antenna reached 

 further than the first leg. This is not always the case but sometimes 

 the antenna reaches even further than in that specimen. Apparently 

 the antenna tends to pass the leg more frequently and fully in 

 C. gallii than in H. euphorbiae. The anal spine varies as in H. 

 euphorbiae, in some being very fine and sharp, in others short and 

 blunt, some present distinct evidence of a bifid tip, but H. euphorbiae 

 does so also. In size, the pupa of C. gallii averages somewhat 

 smaller. It is also possible that C. gallii is a little more flattened 

 dorsally and tapers a little more gradually behind, but, if so, the 

 difference is very slight in either case, and individuals vary more 

 than the average difference covers (Chapman). 



Duration of pupal stage. — It seems almost impossible to 

 accept Mazzola's statement, referred to by Treitschke (Die Schmett., 

 x., p. 131) that he had an example that emerged after being 5 

 years in the pupal stage, but our own records show that the pupal 

 stage may be anything from 15 days to 15 months. Curtis states 

 (on Raddon's authority) that the pupal stage sometimes extends 

 to a second year, and hints that the shifting of the sand on coast 

 sandhills covers up pupae for a great length of time, that they 

 lie hidden and alive, and that the moths do not emerge until 

 brought to light and life by the influence of the elements ! ! Mathew's 

 tabulation (anted, p. 216), also, is most interesting from this standpoint. 

 Of four larvae taken in Capri, in May, 1866, and that pupated at 

 about the same time, one was only in the pupal stage about 3 weeks, the 

 imago emerging in June, the others at long-distant intervals, the last not 

 appearing until October (White) ; at Munich some emerge in late 

 autumn of the year of pupation, others not till after a second winter 

 or even later (Kranz) ; of six larvae taken at Ingolstadt on August 2nd, 

 1892, four pupated August 6th-8th, and one imago emerged August 

 20th, having been only 12 days in the pupal stage (Strohmayer, 

 Soc. Ent., vii., p. 142). The pupal stage in Sicily, in the summer, 

 usually lasts only three weeks (Bartel) ; in Upper Austria the pupal 

 period varies, in 1897 an imago was bred from a pupa 19 days 

 old, but sometimes the pupal stage goes over two winters (Himsl). 

 In the Bilbao district, larvae that pupate in August frequently produce 

 imagines in October (Rossler). 



STRIDULATION of pupa. — Pupae moistened, and when placed 

 in water heard to hiss, sound repeated several times, and resembled 

 that of a snake (Weir, Enl., xiii., p. 218) 



