234 BKITISH BUTTERFLIES. 



numerous ; seen from the dorsum the margin of each segment has six 

 hairs, and there are three or four rows above this on each side. The 

 rows are not very definite, but sufficiently so to give an appearance of 

 white longitudinal lines owing to their white bases, three or possibly 

 four above spiracle. There are four subsegments, the first the largest, 

 the next three narrower, with a flat portion behind the last ; the 

 whole having a convex surface. The hairs are on the ridges of the 

 subsegments and so give also transverse white lines, but both the 

 longitudinal and transverse lines are irregular and vague enough not 

 to appear so until analysed (Chapman). Fourth instar: Length 

 13mm. Eather slender. Colour brownish-green, the green more pro- 

 minent on the dorsal area ; the mediodorsal line dark ; the subdorsal, 

 supraspiracular and spiracular lines pale. Head black, covered with 

 raised lines forming very irregular cells of various contours ; in the 

 cells are small tubercles, each bearing a whitish feathered or serrated 

 seta. The prothorax is narrower than the head ; it carries a black 

 shield which is divided by a pale mediodorsal line, and is furnished 

 with an anterior row of long white bristles, and one posterior long 

 white bristle, besides several shorter bristles ; on the shield on each 

 side of the dividing line is a lenticle ; between the shield and the 

 spiracle is a group of three warts, each with a long seta. The rneso- 

 and metathorax have each four subsegments, while the normal 

 abdominal segments have five, the first of which is very much the 

 larger ; the 8th abdominal has three subsegments and the 9th 

 abdominal apparently but two. The whole surface of the skin is 

 covered with strong spicules, and there is also a covering of white 

 warts, each bearing a white club-shaped seta, the top of which is cut 

 into about five points. There are two sizes of these warts and sette. 

 They are scattered over the general surface without any readily 

 perceivable order. Besides these there are still larger warts w r ith 

 longer setae, which no doubt represent the primary tubercles, and may 

 be found in the same situations as those described in the fifth instar 

 (see below), but the setee of ii and iv are, in the fourth instar, not so 

 deeply cleft at the apex. On the mesothorax in the subdorsal area is 

 a membranous wart with one long hair (seta). On the second sub- 

 segment of the meso- and metathorax are two large ochreous lenticles*, 

 one lower down just above iii, and one on the flange. The abdominal 

 segments have a lenticle just below i, and another on the flange below 

 the spiracle. Above the hooklets on the anal claspers is a large dark 

 tubercle without any seta. The anal comb has about eight teeth. In 

 front of the prothoracic legs is a dark transverse slit, the opening of 

 the chin-gland, which, when everted, shows a pair of deep depressions 

 in the centre. The abdominal prolegs have a complete circle of hooks, 

 which, however, is rather weak on the outer posterior quadrant. 

 [Comparison of fourth with fifth instar : In the fourth instar the 

 prothoracic shield is distinctly divided by the mediodorsal line ; this 

 is much less distinct in the fifth instar. In the fourth instar the 

 lenticles, which, in the fifth instar, occur above the claspers and 

 immediately above the spiracles, appear to be absent. The seta of 

 tubercle ii and that of tubercle iv are not so deeply cleft at the apex, and 



* The lenticles of Hesperia malvae are rather oval with a pale ochreous pleated 

 border, while the sunken disc is finely pitted and deep ochreous in colour. 



