LIFE-HISTORY OF THECLA PRUNI. 27 



{i. e., not confined to one tree or rather bush of blackthorn upon 

 which the eggs are deposited in a wild state) only a single egg is 

 laid on the same fork, or even branch, by the same parent. 



The egg is of a compressed spherical form, 3^2 ^f an inch in 

 width, and -^^ in. high. The micropyle is sunken and finely 

 pitted. The entire surface is covered with raised irregular reti- 

 culations forming a cellular pattern surrounding the micropyle, 

 increasing in size over the rest of the surface into a network 

 pattern, chiefly in the form of hexagons ; at the juncture of each 

 mesh is a raised point with a clefted knobbed apex. The spaces 

 between the meshes are granular. The ground colour is pale 

 buff, the reticulations rust-brown, and the points dark brown. 

 During the winter it gradually becomes paler in colour, being in 

 mid-winter a light greyish ochreous, and the points black at the 

 extremities, appearing to the naked eye of a general light grey- 

 brown. They remain unchanged until hatching about the end 

 of March, being nine months in the egg state. 



On March 26th and 27th, 1905, the eggs hatched. The larva 

 eats away the central portion of the crown of the egg, leaving a 

 comparatively large hole, and emerges. Directly after emerging, 

 it measures ^^ of an inch long, of the usual onisciform shape. 

 The third to ninth segments are humped dorsally, the first and 

 last segments somewhat flattened, and each with a shining black 

 disc. The head is also shining black, and bears a few very tiny 

 bristles. There is a central dorsal furrow and a row of hairs 

 running along each side composed of two hairs on ea,ch segment, 

 both curving backwards, the anterior one being twice the length 

 of the other ; they have black shining pedestal-like bases. Below 

 these is a minute subdorsal hair, almost touching a double black 

 shining wart. The sjDiracles are large and shining black. Along 

 the lateral subspiracular region on each segment is a cluster of 

 four hairs of different lengths, each having a shining black 

 bulbous base, and shorter hairs are scattered over the ventral 

 surface and claspers. The whole colouring is lilac-brown, 

 becoming ochreous on the ventral surface. The entire surface 

 is granular, and covered with minute shining points. 



Just previous to the first moult it measures only ^^ of an 

 inch long. During the first stage it exactly resembles the outer 

 sheath of the bud which remains attached to the base of the 

 young shoot ; these are yellow, with rust-brown tips. The larva 

 is of similar coloration, having the fifth, sixth, and seventh 

 segments light ochreous yellow; the remaining segments at each 

 end reddish brown. First moult occurred on April 13th, the 

 first stage occupying eighteen days. 



After first moult — twenty-five days old — it measures ^ of an 

 inch long. The first and last segments are rather compressed. 

 The back is humped and considerably elevated, with a central 

 dorsal longitudinal furrow. Each hump has a series of sharply 



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