25(3 [December. 



two doubtful questions : (1) What is the natural duration of the life 

 of an Atropos ? and (2) Would the robust constitution, of which 

 proof has already been given, enable it to hold out till the parasite 

 had escaped from its body ? The single perforation of the cuticle 

 necessary to permit the issue of the ichneumon might not be mortal 

 in its effects. The fatal result in other cases is believed to depend 

 partly upon the breaking up of the tracheal system by numerous per- 

 forations, and partly upon exhaustion of the vital forces. The moth 

 in question vi^ould only be subject to the first of these injuries in a 

 very mild degree ; and its great bulk and strength might enable it, as 

 heretofore, to defy the second. It seems, therefore, not unreasonable 

 to suppose that, if left to nature, it would ultimately have recovered. 



Botusfleming Rectory : 



October 21th, 1896. 



TEPHROSIA BIUNDULARIA AND CREPUSCULARIA. 

 BY JOHN" E. EOBSOK, F.E.S. 



I have previously ventured to differ from Mr. Barrett respecting 

 these species. On the former occasion Mr. Barrett told us specimens 

 had been sent him which he was unable to distinguish, but he admitted 

 the examples were selected as a puzzle, and he had no particulars of 

 the time of their occurrence. This seemed to me a very small ground 

 for putting together two species, which, whatever may be the general 

 superficial resemblance, do not occur at the same time of year, and 

 which have a marked difference in colour in a state of nature. Of 

 which, moreover, one species is almost confined to southern woods, and 

 is frequentl}' double brooded (perhaps always), and the other is more 

 generally distributed, but is rarely double brooded, even in the south. 

 Mr. Barrett has now had an opportunity of examining a second brood 

 of both species from one locality, occurring during the exceptional 

 year now ending. He finds them distinctly different from each other 

 and from the early broods ; yet, because the specimens of the second 

 brood of what we call crepuscularia have a white ground colour, he 

 says, " the second brood of the brown crepuscularia is obviously 

 hiundularia,^'' and concludes that " the remaining evidence relied on 

 by those maintaining the distinctness of the two forms, as species, is 

 swept away." 



It may be my dullness, but it certainly appears to me that the 

 evidence in question tells against and not in favour of Mr. Barrett's 

 view. That the second brood in each case differs from the first and 



