186 BRITISH LEPIDOPTERA. 



neighbourhood of the spiracles, which are very light coloured ; the 

 2nd segment (prothorax) has something like a dorsal plate, which 

 is pitchy-red ; the ventral flap and claspers are of the same colour ; 

 they all have a yellowish-white labrum, and the base of the antennal 

 papillae is of the same colour. Collins notes some larvae taken by him 

 near Warrington, as black when captured, but says that they assumed a 

 greenish hue, the black round the pale spots retaining its colour 

 and giving the spots the appearance of having a black ring round 

 them ( Young Nat., ix., p. 204). Syme asserts that, when fullfed, the 

 male larvae are paler than female larvae, and that isolation of a 

 number of the paler larvae resulted in male moths being produced 

 therefrom. 



Development of larval markings. — Bacot's account (supra) is 

 the first detailed description of the larval ontogeny that has been pub- 

 lished. From this we learn that the appearance of the larva varies at 

 each instar as follows: First instar : Pale green, with dark mediodorsal 

 line. Second instar : Dark dull green, a paler mediodorsal stripe, 

 subdorsal and infraspiracular whitish bands, with brighter yellow 

 patches on subdorsal, the precursors of the characteristic yellow 

 spots that appear later. Third instar ; Variable in colour, a pale medio- 

 dorsal stripe, a strongly marked creamy subdorsal band with bright 

 yellow oval spots on the enlarged 1st subsegments of each segment, 

 also an infraspiracular line with a tendency to develop a bright yellow 

 spot beneath each spiracle. Fourth instar: More uniform again, a 

 narrow disconnected mediodorsal line, subdorsal line broken into a 

 chain of yellow spots with orange-red centres ; the infraspiracular band 

 also broken. Fifth instar: Subdorsal, mediodorsal, and infraspiracular 

 lines absent; the subdorsal line of spots strongly developed but without 

 orange-red centres. Syme observes (F.M.M., ii., p. 7) that, when young, 

 the larva of Celerio gallii is exceedingly like that of Sesia stellaiarum, 

 of the same size, being pale or dark green, with a white lateral 

 stripe, but the caudal horn is not blue at the apex as in that 

 species. The yellow spots, he says, sometimes do not appear 

 till the last moult, but generally become apparent at the second 

 ecdysis. May observes (Fnlom., v. pp. 201-202) that larvae of a dull 

 pale green colour emerged from eggs August 1 6th, 1870. First moult 

 occurred August 23rd, the larvae then becoming brighter green ; 

 dorsal, subdorsal, and spiracular lines slightly indicated, being of 

 a lighter colour ; dorsal area darker green ; horn blackish. Second 

 moult occurred August 29th, the larvae now grass-green, the dorsal 

 area darker ; a narrow yellowish-green dorsal line ; subdorsal and 

 spiracular lines pale yellow, edged with black on the upper sides ; 

 ten oval yellow spots, one on each segment, in the subdorsal line, 

 between which and the legs the surface is profusely sprinkled with 

 minute light-coloured specks. Third moult took place on Sep- 

 tember 3rd ; many specimens of a deep sea-green, some lighter 

 and some darker ; the dorsal area always darkest ; dorsal line green- 

 ish-yellow ; subdorsal and spiracular lines yellow ; the ten oval spots 

 larger and of an orange colour; spiracles white; horn black, with 

 the base dirty yellow ; head grass-green ; edge of mouth black ; 

 prolegs black ; some specimens entirely black with the before- 

 mentioned coloured markings ; all have the whole surface sprinkled 

 with more distinct minute pale-coloured specks, most numerous 

 between the subdorsal line and legs. Fourth moult took place Septem- 



