THE GENUS ACRONYCTA AND ITS ALLIES. 125 



on the posterior trapezoidal. The tubercles on this segment 

 and forward are black, and carry single hairs, with a rufous 

 point at the base, those on posterior trapezoidals about the 

 diameter of the larva in length and faintly clavate ; on ii the 

 tubercles are almost evanescent and the hairs small and fine. 

 The second segment has on each side two long distinctly 

 clavate hairs and two simple ones. On 5, 6, 7, 8, 9, 10 and 12 

 the trapezoidal tubercles are very large and packed closely and 

 angulated, much as in the newly-hatched larva, being pyra- 

 midal to the base of the hair^ they form an irregular flat 

 surface on the dorsum bounded by the hair points, on seg- 

 ments 3 and 4 the fused trapezoidals have each two short 

 hairs. 



The spiracles are black, surrounded by a white line, the 

 supra-spiracular tubercle is a black plate with very short hair, the 

 sub-spiracular is in the porcellanous white lateral line and is of 

 same colour, except in 8, g and 10, where it is black, and 

 where the line is interrupted to the posterior margin of seg- 

 ment ; the legs, prolegs and ventral tubercles are black, the 

 ventral surface rufous, except 11, 12 and 13, which are white. 

 The post-spiracular tubercles are very small black plates with 

 very minute hairs. The form of the head is distinctive but 

 difficult to describe without a figure, except as bifid above. 



When the last moult (4th) takes place, the larva in its last 

 skin has at first much of the coloration of the 4th skin, which 

 gradually but rapidly fades, or rather intensifies into the well- 

 known golden and black of the adult larva. Thus the head is 

 brown, the general tint fuscous with broad, white lateral line 

 extending irregularly upwards, and shading off without definite 

 boundary, and involving a great part of loth, nth, 13th and 

 14th segments. 



The yellow plates of 2-9 are brownish, 10-14 pale yellowish- 

 white, and a deep groove separates the anterior from the pos- 

 terior trapezoidals. The spiracular tubercles are white, pro- 

 legs yellowish, and legs yellowish with a black line. 



It is perhaps superfluous to say anything about the adult 

 larva, well-known as it is, owing to its remarkable hairs and 

 striking colour leading to its being observed with care whenever 

 met with ; but a few notes may be useful. In length the full- 

 grown larva is 33 or even 35 mm. Its colours are now changed 

 in a wonderful manner, but it has also lost all those features, 

 which it retained up to the 4th skin, of a young Acronycta 

 larva, ^'Z,cr., its angularity, the whiteness and weakness of the nth 



