26 THE ENTOMOLOGIST. 



TEPHR0S1A CREPUSCULARIA {BISTORT ATA) = T. 

 BIUNDULARIA. 



By J. Arkle. 



Last season I devoted a large amount of time and attention 

 to the Tephrosia question, and as my experience contributed in 

 a great measure to the opinion I now hold that T. crepuscidaria 

 (bistortata) and T. biundularia are one and the same species, I 

 venture to think that what I have to say upon the subject may 

 be of interest to the readers of the ' Entomologist.' First, let 

 it be assumed, but only for the sake of clearness, that T. crepus- 

 cularia (bistortata) is the double- or even treble-brooded insect, 

 and that T. biundularia has only one brood of imagines in the 

 season. 



I had a regular farm of Tephrosias— hundreds of eggs, 

 hundreds of larvae, and many imagines — from Perthshire, 

 Cheshire, Derbyshire, Yorks, Berks, Essex, Somersetshire, 

 Devonshire, Hants, and Sussex. These kept me in such constant 

 watchfulness, that at no time was I able to leave home for more 

 than a couple of days in succession. Besides all this I had a 

 correspondence which may justly be described as voluminous. 

 On all these heads my thanks are due to those who so kindly 

 helped me, and, in addition, my apologies whenever I appeared 

 in the part of the importunate. 



Much has been said of the egg, and I therefore brought all 

 my powers to bear on this initial stage of the insect. I may 

 say, at this point, that my observations throughout were sim- 

 plified by the use of a powerful lens and an excellent binocular 

 microscope. Neither in size, shape, or colour could I distinguish 

 between the egg of T. crepuscularia (bistortata) and T. biundularia. 

 That marvellous faculty of variation, which is such a character 

 of the insect in all its stages except that of the chrysalis, was 

 almost as much in evidence in the egg as in either larva or 

 imago. Sometimes one, sometimes the other, had the advantage 

 in size, greenness, or as regular or irregular ovals or, if you like, 

 cylinders with rounded ends. Fourteen laid by a Delamere 

 Forest female were the palest. Quoting from my note book, I 

 find them described (May 10th) as " pale, dull straw-colour, very 

 nearly that of the chip box on which they were laid. Their 

 shells have a very faint iridescent green, only visible under a 

 strong lens." As a rule the eggs were enveloped in a whitish 

 "fluff" or down, but even this feature was inconstant. It was 

 Dr. Biding who discovered this " silk " to be " contained in a 

 pouch at the extremity of the abdomen, in the form of dense 

 bundles about 2 mm. long, and resembling, in miniature, locks 

 of wavy flaxen hair. Hitherto all such coverings were supposed 

 to consist of scales from the anal segment " (Entom. Kecord, 

 ix. 130). 



