EUTRICHA QUERCIFOLIA. 213 



the 3rd abdominal the posterior fork of process is very slightly 

 larger than the anterior; on the 4th, 5th, and 6th abdominal 

 segments, both arms of the twin processes are about equal, and 

 they are, as are also those on 3rd and 8th, very much smaller than 

 the others : on the 8th the process is not twin or double, though 

 there is a small process or fleshy lateral wart at a 

 higher level. All the lateral hairs point downwards, and those 

 at either end point backwards and forwards respectively in addition ; 

 the processes can be moved at will of larva ; when resting, the larva 

 depresses them, and the hairs, in consequence, are curved beneath 

 it, and touch the twig on which it rests ; when the larva crawls or is 

 about to shift its position, the processes are slightly raised and the 

 hairs jut outwards from the body ; these movements are best observed 

 with regard to the processes on the ist abdominal segment which 

 bears the long pencil-like tufts of black hairs ; on the other segments 

 the movements are not nearly so noticeable. Ocelli : Shiny raised 

 buttons forming a curved row of four in front, and an isolated one 

 behind. Legs : These are difficult to examine, as they are completely 

 hidden when at rest, and the larva has to be forcibly turned over 

 before a glance can be obtained. The legs are black, shiny, and 

 end, so far as one can see, in a single hook. Prolegs : Yellow, with 

 a black oblique stripe at front and back ; the foot has a tendency to 

 be JL-shaped, and the hooks run round the outer margin. (It is rather 

 difficult to describe the foot of living larvae, as it greatly alters its 

 shape and appearance according to the surface and position of the 

 object to which it is attached.) Venter : The ventral side of lateral 

 processes is very pale grey, almost white, and contrasts strongly with 

 the velvety-black of the ventral surface of thorax ; the abdominal seg- 

 ments also have the centre of ventral area black, but the inner side of the 

 prolegs is yellow, and the intersegmental areas are also pale (yellowish). 

 It is difficult, however, to accurately describe the ventral colours, as a 

 larva, when turned over, almost immediately regains its natural position. 

 There can be little doubt, however, that these strongly contrasted — 

 black, white, and yellowish — ventral colours are startling*, and give the 

 larva a formidable appearance if it should by any chance become 

 detached from its resting-position, more especially as it wriggles 

 vigorously if removed from twig or resting-surface. Larval scales^ : 

 The larva has some deep metallic blue hairs very similar to those 

 of Dendrolimus pini\ when at rest nothing is to be seen of them, 

 but, if disturbed, the larva arches its thoracic segments ; this opens 

 the folds of skin on the meso- and metathorax, exposing the well-known 

 velvety blue-black and orange markings of these segments, and at 

 the same time a rather formidable array of blade-shaped hairs ; as 

 the larva sinks back into its resting-position, the skin folds gradually 

 and the hairs are sheathed and the velvety-blue slit-shaped 

 markings hidden from view (Bacot, September 28th, 1897). Adult 



* Some, if not all, of the larvae of Catocala have pale grey or whitish under- 

 sides, with a black blotch or spot on most or all the segments ; this, one may 

 suppose, is a parallel development to the contrasted ventral coloration of the larva of E. 

 quercifolia, their habits, and consequently their protective needs being so similar ; 

 the habit of wriggling if knocked or jarred off the resting-place is still more noticeable 

 in the larvae of the Catocalids than in that of E. quercifolia. 



t Packard deals with these scale-like setae at length (Ann. Mag. Nat. Hist % 

 (6), ix., p. 373), and gives illustrations of them. 



