2 [January, 



BACOTIA SEPIUM, Spe., IN THE NEW FOREST, WITH NOTES ON 

 ITS CHARACTERS. 



BY T. A. CHAPMAN, M.D., P.Z.S. 



Mr. Fletcher has just kindly sent me for examination the speci- 

 mens of a Psychid that are recorded by Mr. Barrett in Ent. Mo. Mag., 

 December, 1895, vol. xxxi, p. 275, as Fumea hetulina. 



These examples are three males, one female, two blown larvte and 

 cases, one other case wnth empty female pupa skin, and a male pupa 

 skin, supplying very complete materials for their determination. 



They prove to be Bacotia sepium, Spr. (= tahulella, Bruand). 



In pointing out that they are not hetulina, it seems desirable that 

 I should go into some detail as to the points of distinction between 

 hetulina and sepium, and mention those characters that may be 

 observed in these specimens as they stand, that prove them to be 

 sepium and not hetulina, as my mere ipse dixit would be of little 

 weight against the authority of Mr. Barrett, whose work in this group 

 is so distinct an element, leading up to our recent more definite 

 knowledge of the rarer and more obscure British Psychidce. 



The Case. — These cases are of peculiar form, short and wide, even a shade 

 protuberant beyond the middle, and ending in a blunt rounded extremity, without 

 any previous tapering, carried nearly vertically to the surface, absolutely so when 

 fixed for pupation, as the specimen afExed to its bit of bark shows, in the instance 

 of the empty female case. The case of hetulina tapers definitely towards the free 

 end, and is more slender and spindle-shaped, though often at some angle to the 

 surface, it is never carried or fixed vertically to that surface, except, as also occurs 

 in nitideUa, such a position enables it to hang vertically downwards. The clothing 

 of the case is distinctive. NitideUa clothes the case with grass straws, making the 

 case look like a bundle of yellow sticks ; sepium attaches various pieces of blue-grey 

 lichen, well illustrated in two of these New Forest cases, the third has a bit of bark 

 attached ; hetulina never, well, hardly ever, uses either grass or lichen to clothe its 

 case, but bits of bark, rotten wood, brown dead leaves, and so on, often looking very 

 dirty and smoky from the materials used; brighter and pleasanter to appearance 

 when leaf material predominates. 



The Larva. — The larva of sepium has a black head and thoracic plates, re- 

 lieved on the thorax by only a median whitish line ; hetulina has brownish subdorsal 

 marking, approaching those of nitideUa larva. In sepium the third thoracic plate is 

 represented by only a small scrap on either side, in hetulina it is complete across the 

 dorsum, as in nitideUa. The colour of the abdominal segments in sepium is sepia ; 

 in hetulina it is a ruddy or pinkish-brown. Their structure is also very different, 

 the abdominal segments in hetulina are divided dorsally into two distinct ridges, or 

 subsegments carrying respectively the anterior and posterior trapezoidal (I and II) 

 tubercles. In sepium there is no such definite division, and the tubercles are in 

 transverse alignment (approximately) with the anterior tubercle (I) external. The 



