CELASTEINA ARGIOLUS. 441 



simpler than those of the upper-surface ; it requires close scrutiny to 

 avoid describing them as unspiculated ; their bases are usually simple 

 cones (non-stellate) ; these hairs are often long, up to 0*35mm., these 

 belong to the region of tubercle vi. The skin-surface is still reticulated, 

 but the pattern consists of a number of circles (or approximate curves, 

 ellipses, etc.) crowded together, but leaving angular spaces where three 

 or more meet ; near the bases of the (true) legs the circles are less 

 visible, but a number of points are distinct, apparently at the spaces of 

 intersection, but whether they are spicular depressions, or mere optical 

 results of different densities, is not at all plain. Near the anal region 

 are some unmistakable, very sharp, skin-points, on rounded bases, 

 arranged in orderly rows ; what, if any, relation these have to the 

 circles of the reticulation is not determined. The spiracles, as seen in 

 a cast skin, are remarkable structures ; they rise as conical projections 

 with very thick walls ; these walls, however, are cellular, having what 

 may be described as two or three horizontal floors (parallel with skin- 

 surface), and about seven vertical ones, though it may be, owing to 

 difficulty in interpreting appearances, that there are seven radiating 

 pillars in a circle round the top, and others lower down ; the skin 

 envelops, but is distinct from, this chitinous framing. The pads of the 

 prolegs each have six, seven, or eight hooks (varying), and they distinctly 

 tend to be alternately larger and smaller ; in the previous (2nd) instar 

 this was only faintly indicated. Fourth instar (June 10th. Just 

 moulted into last instar) : Length, 7mm. ; height, 2mm. ; width, 2*4mm. 

 Head black, shining. On dorsal view, the larva is of nearly equal width 

 from mesothorax to 7th abdominal segment ; the dorsal ridges are quite 

 rounded, not very close to each other, and separating from 1st abdominal 

 forwards ; the interspace not hollowed ; the width about one-fourth of 

 slopes ; the slopes hardly convex. On lateral view, the larva is highest 

 about metathorax, and falls slightly to the 7th abdominal segment. The 

 mesothorax markedly rises above prothorax ; the mesothorax and the 

 seven following segments have dorsal ridges, slightly humped ; the 

 7th, 9th, and 10th abdominal segments slope backwards, and show 

 little of dorsal ridges. The colour is dark green, relieved by the 

 numerous golden hairs, and by a broad dorsal band of red- brown down 

 the dorsal plain on the humped segments, the three forward ones 

 having a central green spot, and the others green at their margins, 

 dividing the band into a patch on each segment ; there is also a 

 pink suffusion along the lateral flange, darkened to almost black 

 at the posterior margins of the 5th and 6th abdominal segments. 

 [Larvae taken at Moncayo, on heath, varied a good deal in the 

 amount of colouring.] [The larva, under observation at the 

 moment, was deprived (for mounting) of its cast-skin, and is now 

 searching about the site of its silken pad most anxiously, doubtless 

 looking for the skin with a view to eating it, which its fellow is now 

 vigorously doing with his.] The red colouring affects hairs and hair- 

 bases, as well as the skin proper. On the slopes are " oblique " lines ; 

 the outer sides of the dorsal ridges have some whitish coloration, 

 wider at the posterior borders of segments ; beneath this a faint ruddy 

 tinge, and then a paler green shade on an oblique line, and lower, near 

 spiracular level, another. Down the middle of each segment, on the 

 " slope," is a subsegmental groove. The hairs, with their stellate 

 bases, are packed together absolutely closely (to be further apart as 



