178 THE entomologist's record. 



species and reported to me ; Mr. Prout confirming my observations, 

 Dr. Eidino- sayine; that in the larvfe he was rearing he did not find 

 this difference, the A in the larvae of T. histortata being frequently 

 open at the top. I therefore made a careful examination of 102 larvre 

 of the second brood of T. histortata, while in their third and fourth 

 skins. 



Dr. Riding had pointed out that in T. histortata, the oblique lines 

 forming the sides of the A run into the dark lines, bordering the 

 medio-dorsal band, at or near the apex of the A. This is quite 

 correct ; but I found that the area of the medio-dorsal band at 

 the juncture of the lines forming the sides of the A, and often 

 for a short distance above was suffused with dark umber, or, in 

 many cases, with the same intense velvety black, as the rest of the 

 marking, thus forming an inverted Y with a short foot, rather than a V. 

 In a few instances, with larvte having the apex of the mark dark 

 umber instead of black, there is an actual opening, although it only 

 amounts to a narrow pale streak down the centre of the medio-dorsal 

 Imnd. But this gap or streak of pale colour is very different from the 

 wide and distinct gap that is present in this mark in larvae of T. 

 crejjnscniaria, and in no case did I find a larva of the last-mentioned 

 species with the central area closed or extended above the apex of the 

 /\. The proportion of larva? with : (1) The apex and extension of A 

 as dark or almost as dark as the sides. (2) This area distinctly paler 

 than the remainder of marking, but still much darker than the ground 

 colour of the larva. (3) A narrow streak through apex, as light or nearly 

 as light as ground colour of the larva worked out as follows : (1) 46 larvae, 

 or 46%. (2) 49 larva?, or 49%. (3) 7 larvas, or 7%. The paler larva? as a 

 rule had the A of the type 1, while those with the 2 or 3 type of marking 

 usually had the ground colour of a darker tint. There is also a ten- 

 dency with many larva? of T. crepuscuJaria to entirely lose this mark, 

 while with larvffi of T. histortata, though present, it is less strongly 

 developed, and applies only to a small proportion of the larva?. 



The larva? of T. crepuscuJaria I found tol)e slower in feeding up, 

 and very much more difficult to rear under unnatural conditions, and, 

 although treated in exactly the same manner as those of T. histortata, 

 a far larger proportion died before pupation. My experience with 

 larvae of the two species reared during 1897, from the same stocks 

 agrees exactly with what I have noted above concerning the 1896 

 broods, and the larvfe of a brood of T. histortata reared from ova laid 

 by Scotch parents, which Mr. Hewett was kind enough to forward me, 

 agreed with those of the Clevedon stock. 



My thanks are due to Mr. Christy for a batch of ova of T. crepns- 

 cnlaria laid by parents which emerged on the 30th April, the progeny 

 of a $ taken on the 4th March, 1896, in West Sussex. A few of the 

 larvae of this brood differed greatly from the remainder. I noted, on 

 June 18th, that one larva had the A marking of the typical T. histor- 

 tata type, joined at ai)cx, and with a well marked extension at this point ; 

 two or three other larva? had traces of this character, but very faintly 

 marked, while the remainder differed in no respect from tyjiical larvroof 

 T. crepuscuJaria, having a wide gap at apex of A- Unfortunately 

 this lirood was rather unliealtby, and as I was unable to give them 

 much attention, they all died. The divergence of a few larva? in the 

 last-mentioned brood from what I considered to be a stable feature. 



