236 BRITISH BUTTERFLIES. 



covered with numerous pits divided from one another by high walls ; in 

 each pit is a black bead-like tubercle which carries a pale seta ; the 

 seta is flattened and pointed, plain on one side and serrated or toothed 

 on the other ; besides these, there are several longer quite simple 

 setae. On each side of the face, not far from the centre, are two 

 round lenticles and another above the ocelli. The whole surface of the 

 skin of the larva is covered with strong spicules ; these seem to be 

 formed by the skin being pinched up, as it were, to a point, and forming 

 thereby rays of folded skin running from the point to a short distance 

 all round. One use of these spicules is no doubt to strengthen the 

 skin and yet leave it perfectly pliant. Thickly scattered all over 

 the surface, at more or less regular intervals, but more especially on 

 the ridges of the subsegments, are milk-white tubercles, each crowned 

 with a single somewhat glass-like seta. The tubercles are of two 

 sizes, all smoothed and much raised above the general surface of the 

 skin, which, immediately surrounding them, is pale in colour. The 

 corresponding setae are also of two sizes, though intermediate sizes also 

 occur. The smaller (Olmm.) and the larger (0*24mm.) setae are 

 similar in structure, and there is no doubt that they are of secondary 

 nature. They rise from the summit of the tubercles, are stout and 

 bristle-like, and expand at the apex, where they form a depression 

 surmounted by usually five conical teeth. Round the legs, claspers, 

 and beneath the larva, these secondary setae, though similar in other 

 respects, are not expanded at the apex, but run gradually to a single 

 sharp point. Besides these, there are still larger tubercles bearing 

 longer setae of a distinctly different form. These may be the primary 

 tubercles. The single seta of these tubercles is flattened towards the 

 apex, but not expanded, and the apex is deeply cleft, so that there 

 are only two long slender teeth, though sometimes the two teeth are 

 short and conical. When the teeth are long and slender they some- 

 times lie so close together that the seta appears to end in a single 

 point. These setae occur in the following positions : On the meso- 

 and metathorax, there is a pair on the dorsal area of the second sub- 

 segment, one on each side of the mediodorsal line, and another pair, 

 wider apart, on the 3rd subsegment ; these appear to be the trapezoidals 

 i and ii. On the lateral area there is a tubercle which looks like an 

 accessory tubercle, situated on the spot where the spiracle would be if 

 these segments bore spiracles. On the flange are two tubercles a little 

 distance apart, which may be iv and v, and below is another, which 

 may be vi. On the abdominal segments, i is on the 1st subsegment, 

 but ii with a very long seta, retains its position on the 3rd subseg- 

 ment, iii is above and in front of the spiracle, iv with a very long seta 

 pointing backwards, and v with a shorter seta directed forwards, are 

 subspiracular and some distance apart, and vi is below these with a 

 rather long seta. The seta of tubercle ii and that of tubercle iv measure 

 0-4mm. in length, and those of the other tubercles i, iii, v and vi about 

 0'3mm. The prothorax consists of four subsegments, the first two 

 being very small, and having the appearance of wrinkles; the third 

 is large, and bears the transversely elongate shield, a raised tubercular- 

 like swelling just below the shield, crowned with a lenticle and three or 

 four long setae and some shorter ones, and the large oval spiracle 

 which lies towards the hind margin. The shield bears eighjfc strong 

 whitish setae and two minute black dots on its anterior border, and 



