APPENDIX. 477 



is still green with a yellowish ring at the junction of the segments 

 where the skin overlaps; a dark (? structural) mediodorsal line, and a 

 broad white subdorsal band (of the Sesia stellatarum pattern) running 

 up to the base of the horn. The caudal horn itsell has a pink stripe 

 up the front and back and is entirely crimson at the tip, but is whitish on 

 the sides from the base upwards for more than half its length. The 

 spiracles are whitish or pale pink bordered by a black rim. There are, 

 as yet, no lateral or spiracular bands, nor oblique stripes, but the larva 

 is speckled with the white bases to the hairs. The general appear- 

 ance of the larva is Eumorphid, but the coat of fine bristles 

 with their forked tips gives the portion viewed with a strong 

 lens an Amorphid appearance. [The most noticeable larval habit 

 at this time is that of dropping without using a thread ; the 

 larvae appear to hold on very loosely and to drop at the 

 slightest touch or disturbance; no silk is used even when the 

 larvae are about to moult.] The ventral area is dusky and, after 

 the next moult, becomes very dark olive-green, so dark that, a 

 a casual glance, the colour gives the impression of black. Third instar: 

 The larger of two larvae in this instar is quite 12 -5mm. in length, or, 

 including the horn, which projects somewhat, 15mm. It is less evenly 

 cylindrical, and has, consequently, lost much of its Eumorphid 

 appearance ; the 2nd, 3rd, 4th, 5th and 6th abdominal segments 

 being larger, especially the 3rd, 4th and 5th, the larvae taper slightly 

 to the head, and more noticeably to the base of the caudal horn. 

 The horn is longer, larger at its base, tapers to a point, is stiff, 

 and has a backward curve. The colours are much as before, 

 but brighter and with more prominent white specks, whilst the 

 spiracles are situated in dark red oblique slashes, the slope of the 

 latter being from head to anus ; these slashes occur on abdominal 

 segments 1-7, and are strongest on the segments that bear the 

 prolegs. The secondary hairs are now shorter and smaller but 

 still distinctly forked at the tip, the smaller dark-coloured and 

 without marked bases, the longer and paler hairs with marked 

 mammillary bases of an opalescent white colour, the latter are 

 fewer in number, about 1 in 3; the larger mammillary-based hairs 

 are situated on the top of the subsegmental ridges and exhibit the 

 normal 8 rows to each abdominal segment. There is no marked 

 tendency now for the first three subsegments to coalesce so that 

 the Eumorphid characters would appear to be waning and the 

 Amorphid to be increasing. The shorter hairs on the head and 

 on the scutellum are still notched at the tip, the longer ones being 

 simple, but this difference is not maintained on the body-segments, 

 where the longer ones are, if anything, the more noticeably forked, 

 the smaller dark hairs apparently representing a dwindling phase 

 of this character. [This is suggestive of the change which takes 

 place in Amorphid larvae after the 1st moult, whilst the same 

 accentuation of a portion of the bristles of the 1st instar occurs, 

 but the hairs of the larva of H. tityus are now as numerous as 

 those of Amorphid larvae in the 1st instar, and larger proportionally, 

 the forking being much more noticeable, although, of course, bearing 

 no comparison with the forked character of the primary hairs which 

 the larva of H. tityus has in its 1st instar when the forks are longer 

 than the stalk of the hairs. As regards the development of secondary 



