THE GEXUS ACRONYCTA AND ITS ALLIES. 249 



segment. The legs of 4th segment touch or cross the prolegs 

 of 7th. The head is prone (vertex backwards, jaws forwards), 

 and in connection with this there is a certain amount of retrac- 

 tion of the 2nd segment within the 3rd, and even of 3rd within 

 4th, so that the dorsal tubercle of 3rd, instead of facing upwards, 

 faces forwards, being on the edge of the fold formed by the 

 front of the segment being folded inwards. The long hairs 

 directed forwards are those of the 3rd segment. These hairs 

 measure nearly 8 mm., those on 12 and 13, 5-6 mm., the others 

 along the dorsum 2-3 mm. The rich chocolate back has the 

 same outline as in the previous skin, and the tubercles are light 

 and dark in the same way ; the tubercles in it are black, often 

 with a pale or even nearly white point at the base of the hair. 

 The band is bordered by a yellow line, which is orange close to 

 the chocolate band. There is also a tendency to a pale dorsal 

 line. The nth segment still has hairs much shorter than any 

 other, the 12th segment forms quite a hump, culminating at 

 the posterior trapezoidals. It may be noted that all the tuber- 

 cles remain very distinct, more so indeed than in any other, 

 even alni or niegacephala, and do not become fused or lost as in 

 psi or leporina. The posterior trapezoidals in 5 form prominent 

 projections, but that segment can hardly be called humped ; 

 8, g, and 10 have similar though smaller prominences. The 

 spiracles are white in a black circle, that on 12 very large and 

 distinct. Prolegs with a beautiful pink tint. Head in one or 

 two nearly black, on most deep umber on vertex, passing into 

 peach towards the mouth, and with varying amounts of black 

 marbling. The form, and in some instances marking, very 

 like niegacepJiala. In one specimen the green is overlaid by a 

 deep smoky tint, but not so dark but that the dorsal band with 

 its paler margin is easily distinguishable. The whole surface 

 is studded with the minute hairs or hair points noticed in the 

 last skin ; these are black and more pronounced in the dark 

 dorsal streak. One of small ones laid up for moult August i6th. 

 August 17th. — Two small are laid up. August i8th. — All the 

 smaller laid up except the ist ; which has changed into the last 

 skin, so that it is now obvious that the mass are 4-moulters, 

 the 4 exceptional ones 5-moulters. The 5-moulters in 5th 

 skin do not differ much from 4th skin, the broad stripe on 

 back is less deep in colour than in last skin, less definite in its 

 margins, and has not the distinct orange and red margin of 

 dorsal line. On the loth segment the posterior trapezoidal, 

 though within the brown band, is green, and looks like an inva- 



