^^ AND -^^ 



JOURNAL OF VARIATION. 



Vol. IX. No. 4. April 15th, 1897. 



Contributions to the life=history of Thecla pruni. 



(Illustrated hij Plate J. 



By J. W. TUTT, F.E.S. 



I. — The full-fed larva of Thecla pruni. — The larva of Thecla 

 pruni, in its last skin, is of a lovely delicate green, with a tinge of 

 yellow in it, especially laterally, the sides ending below in a pale 

 tumid sub-spiracular ridge. It is well supplied with short brown 

 hairs. The ventral surface is much paler, i.e., is of a whitish-green, 

 rather than yellowish -green ; it is also very glassy, and the skin is 

 more sparingly sprinkled with pale glassy-looking hairs. 



Head. — The head is very small, of a very pale whitish-brown hue, 

 the mouth-parts darker brown ; the ocelli are transparent, placed on 

 two black lunules, one on each cheek, five ocelli being arranged in an 

 arc on the side nearest the mouth, a sixth being separate, and placed 

 by itself on the side of the cheek remote from the mouth. 



The head is sprinkled with a number of glassy-looking hairs. It 

 is quite retractile within the prothoracic segment, but is extended to 

 some distance beyond the pro-thorax when the larva is attempting to 

 find a crossing from one leaf to another. 



Thorax. — The front edge of the pro-thorax is also studded with 

 glassy-looking hairs, similar to those on the head, but further back 

 (dorsally) the pro-thorax becomes covered with short, black, curved 

 bristles. The segment itself is very extensible, and stretches con- 

 siderably when the larva is actively moving. The true legs are very 

 pale and glassy, well-sprinkled with long glassy hairs, and terminated 

 with a dark brown retractile hook. The meso-thorax and meta-thorax 

 are flattened dorsally, although the segmental incisions are very deep, 

 and there is a gradual rise from the head to the second abdominal 

 segment. 



Abdomen. — The 2nd, 3rd, 4th, .5th and 6th abdominal segments 

 bear a double ridge of raised dorsal serrations, the raised points 

 decreasing in size on the 5tli and 6th abdominal segments. These 

 are distinctly separated by the deep segmental incisions, and by the 

 fact that they do not extend so far forward as the 1st sub-segment of 

 each segment. The apices of these raised projections are edged with 

 purplish-red internally, and yellowish externally, and are well sup- 

 plied with purplish-red hairs. The spiracles (on the 1st, 2nd, 3rd, 

 4th, 5th, 6th, 7th and 8th abdominal segments) are very minute, 

 scarcely to be detected by the naked eye, but, under a one-sixth lens 



