PEOUTIA BETULINA. 289 



with which it is clothed are also very fine, there being only one tiny 

 scrap of coarser material. These Luffiid characters are also more or 

 less noticeable in the higher Macro-Psychids, the young larvaa of which 

 carry their cases perpendicularly to the surface on which they travel. 

 The young case of P. betulina differs from that of L. lapidella, of 

 similar size, in being very slender and very slightly (if at all) wider at 

 one end than the other (Chapman). Compared with the cases of P. 

 betulina, those of B. sepium are short, wide, slightly protuberant 

 beyond the middle, ending in a blunt rounded apex, they are carried 

 vertically and are fixed so for pupation ; the cases of P. betulina taper 

 definitely towards the apex, are more slender and spindle-shaped, 

 carried at an angle to the surface, not vertically, unless its weight 

 allows it to hang vertically downwards. The case of B. sepium is 

 covered with pieces of lichen, whilst that of P. betulina is clothed with 

 bits of bark, rotten wood, brown dead leaves, and looks very black and 

 dirty owing to the material used. 



Laeva. — The head black, with one pale line on each side of centre, 

 outside the clypeus ; the 1st joint of the labrum and the bases of 

 antennae pale ; the prothorax dark (nearly black) , with central and two 

 lateral (or subdorsal) pale bands, the dorsal wider behind, very narrow 

 in front, the lateral irregular and interrupted in the middle by a dot ; 

 these pale and dark bands run down the meso- and meta thorax on the 

 intervals as well as on the plates ; on these is a third pale band at 

 margin of plates, above lateral plate ; the second dark band forms a 

 large, square, blackish patch on the plates at their lower portion, omit- 

 ting (in full darkness) the anterior margins of plate ; the markings 

 are paler on the meso- than on the prothorax, and on the meta- than 

 mesothorax. The abdominal segments are dark reddish, or reddish- 

 chocolate, very decidedly bisegmented, having pale (not punctated) 

 spots in row in division between subsegments and in groove above flange ; 

 there is a very conspicuous dot where these two grooves meet. They 

 occur also along the anterior margin of segment, and in the grooves of 

 flange and beneath (apparently the same pattern as in larva of F. casta). 

 The general aspect of the true legs very dark, but the joints paler 

 brownish. The longitudinal flange is made up of three elements, the 

 central one being straight, narrow and high, the others squarer and 

 flatter. The anterior trapezoidal tubercles (i) outside the posterior (ii), 

 and with shorter hairs ; iii on upper ridge of flange carries a strong 

 hair (Chapman. June 12th, 1899, from larva taken by Prout at Ching- 

 ford). A description of a second adult larva reads as follows : Almost 

 fullfed, 6mm. long. Head absolutely black (with a very narrow pale line 

 each side of clypeus) except that the antennal bases and the base of 

 labrum is pale or white. The prothoracic plate also is black, with a 

 pale dorsal line, very slender at anterior margin, so as to be indistinct, 

 and no subdorsal line (except a faint suggestion at the posterior 

 margin). The prothoracic plate is brown rather than black, with very 

 slender dorsal line, the subdorsal line also faint, curved, and very 

 narrow ; the second plate below this, black, and the divisional 

 membrane round this plate pale, the dorsal and subdorsal lines strong 

 on the membrane between the pro- and mesothorax. The metathorax 

 not so dark, but the pale lines still very narrow and weak ; the sub- 

 dorsal somewhat diagonal ; a delicate plate in prespiracular region as 

 on mesothorax. The membrane around prothoracic shield, in front and 



