494 BRITISH LEPIDOPTEEA. 



the back of each segment, preceded and followed by semi-lozenge- 

 shaped spots, which unite (or nearly so) with those of the following 

 and preceding segments ; the anterior spot terminates lower down the 

 segment than the posterior. On the thoracic segments, the dorsal line 

 is so narrow and dusky as to be hardly perceptible. Below the dorsal 

 rows of black spots there is a longitudinal line of the ground colour, 

 with a bright yellow spot in each segmental incision, formed by the 

 hind margin of each segment. Below this is another row of black 

 spots on each side, composed of two spots on each segment, which are 

 confluent, or nearly so, at their lower extremities, and giving them, when 

 confluent, a horse-shoe appearance. In this row of black spots the 

 spiracles are placed. This spiracular row is followed in turn by 

 another longitudinal band of the ground colour, in which, on each 

 segment, are two subspiracular black dots, one on the anterior and 

 one on the posterior fold, the anterior dot being placed rather lower 

 than the other. The space between this band and the prolegs and 

 true legs is nearly filled up with blackish and dusky markings, some 

 segments being more suffused than others. The prolegs and ventral 

 area pale, with a row of dusky dots down the medio ventral line." 

 Boisduval describes the larva as " verte ou d'un jaune verdatre plus ou 

 moins clair, pubescente comme ses congeneres ; elle a quatre lignes de 

 points noirs, dont deux dorsales et les autres laterales ; on remarque 

 en outre sous le ventre un petit point noir sur chaque anneau." The 

 X-like dorsal marks, the lateral horse-shoe-shaped spiracular spots, 

 the ventral " petit point noir " are all very characteristic of the larva 

 of this species. 



Comparison of A. trifolii larva with that of A. palustris (trifolii- 

 major). — The larva of A. trifolii is smaller than that of A. palustris 

 {trifolii-major). The latter has the black dorsal spots on each segment 

 separate, whilst the former has them united and X-shaped. The larva 

 of A. trifolii-major has the spiracular row of black spots such that there 

 are two distinct spots on each segment ; in that of A . trifolii they are 

 united into a spot, the form of which roughly resembles a horse-shoe 

 (Briggs). We can corroborate Briggs entirely as to the general constancy 

 of these differences, although it would appear that in some larvae of 

 palustris the spiracular spots attain the horse-shoe shape, and it is 

 possible that the intermediate races would, in their larvae, show inter- 

 mediate characters. The comparison of the larva of A. var. syracusia 

 with that of A. palustris, given under the latter species, is practically a 

 further differentiation of the larvae of the two forms here considered. 



Comparison of A. trifolii larva with that of A. filipendul.f. — 

 Hellins thinks that the X-like character of the black dorsal markings 

 (when the segmental incisions are hidden) is the chief distinction 

 by which the larva of A. trifolii may be distinguished from that 

 of A. filipendulae, the dorsal rows in the latter being formed of a broad 

 and a narrow spot on each segment. He further states that the former 

 is smaller, the ground colour probably more yellow, and the black 

 spots in the lateral rows also smaller than in A. filipendulae. 



Cocoon. — The cocoon is of the same general form as those of the 

 allied species, but those described, received from Mr. Christy, were 

 spun up on a piece of leno, and not attached to a grass-culm or stalk of 

 some herbaceous plant. They are smaller than those of either A. filipen- 

 dulae or A. palustris, averaging about five-sixths of an inch in length 



