AEICIA MEDON. 



267 



of darker dorsal line and a depression near spiracle with surrounding 



rampart. September 26th. — Has moulted this morning, had not done 



so last night, the long resting period is remarkable, the weather having 



been the warmest of the year, about 65° average, in room where larva is. 



In the second instar the hairs are long and well but finely spiculated ; 



on the 7th segment the honey-gland replaces dorsal hairs, though there 



are two in front of it, that may be i, but are probably the accessory 



pair in front of i, but iii is a well-developed hair nearly as long as i 



The condition in third instar is the same except that iii (on 7th 



abdominal) is represented by two hairs. There are five instars, but 



my notes and specimens of the fourth are very deficient. My 



specimens, however, suffice to show, by the sizes of the heads, that there 



are five instars. In the last instar the special angular hair of the 



prothorax has a dark base with a beautifully crenulated margin, and 



the radially arranged skin points about it complete — an elegant object 



when properly magnified. The " fan " or scent gland is well 



developed, each hair of this seems to terminate in a flat disc slightly 



larger across than the thickness of the hair, and with a central 



aperture, or almost a trumpet-like extremity. The honey-gland has 



the usual four circles with four accessories, centrally within it (tubercles 



i and ii modified ?). It is surrounded by a fairly complete row of 



lenticles, and has also some half-dozen short hairs (about O-lmm. long) 



whose terminal halves form quite a brush of fine long spicules. There 



are other short hairs, clubbed, bent, and clothed with short spicules. 



The lenticles, which also are frequent near the spiracle, are often quite 



circular with broad smooth borders, but others are variously angulated 



(representing the spines on hair basis), even exactly triangular, or 



square, or intermediate; with several (to six or eight) little knobs on the 



margin. The hairs are usually pointed, the smaller ones often 



markedly curved, and all spiculated. The bases are sometimes smooth, 



usually so on the front segments, and vary to a stellate structure, which 



is more usual on the posterior segments, where some very marked 



forms occur. Each pad of the prolegs has about five large and five 



small hooks alternating. In the first instar there is a large and a 



small, occasionally a large and two small. In the second are still only 



two. In the third instar sometimes two hooks sometimes three, 



one larger than the other. In the fourth they vary from two 



large and a small to three large and two small. The head is 



always black. But one might fill many pages with these structural 



details of the larvae, and must be satisfied with leaving further 



details to be gathered from the photographs (Chapman). — Larva before 



and after hybernation. — A well, or full-grown larva in third instar on 



Erodium cicutariuin, October 3rd, 1907, 4mm. long, probably more if 



extended ; l*5mm. at thickest, about 1st abdominal, on dorsal view, 



narrows slightly and gradually to 7th abdominal (about l-2mm. across), 



thence rounded. Each segment presents a marked rounded 



prominence on either side in the line of the dorsal flanges, making a 



dorsal groove between them ; these project well over prothorax, in a 



a way approaching Strymon, incision well marked both across back and 



along lateral flange. The colouring makes the insect from above seem 



very flat, and the lateral flange does project a little laterally, i.e., the flange 



projects outwards from the bottom of the "slope " with a re-entering 



angle ; but the larva is really nearly as high as broad. Colour a pale 



