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, 9 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 ii, 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 P^-le 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, its angularity, the whiteness and weakness of the nth 
