1895.] 69 



first stage, bnt tbcrc is no reason to doubt their accuracy. When 

 more advanced the larva? present the following characters: — 



A. BHASSIC-i;. 



Oral, convex, pale greenish-yellow, smooth, marginal field narrow ; the margin 

 itself without a waxen fringe (but it may have existed at a previous age) ; the head 

 rounded in front, with several short, hairlike projections ; the median dorsal area 

 throughout with a series of long, rather blunt, transverse dentations (resembling the 

 vcrtebrfe of a sole), laterally connected, slightly raised, not extending wholly across 

 the median area. This structure is most percepticle in the adult form, increasing in 

 distinctness as (he pupa state is assumed beneath the larval integument, when also 

 the eye-spots become brown and are more evident. The adult form is not described 

 by Signoret. 



A. PROLETELLA. 



Oval, convex, pale greenish-yellow, smooth, marginal field narrow, but rather 

 broader than in brassicce, on the margin a white waxen fringe, which is deciduous 

 but persistent almost to the last ; median dorsal area throughout with a series of 

 small, transverse, parallel ridges, not shortened or blunted as in brassicce, but ex- 

 tending quite across the dorsum, indicating the segments of the insect beneath the 

 integument, these dorsal characters become more distinct as the insect develops ; the 

 rest of the surface delicately striate. The head less rounded in front, has there a 

 few short hairs. Eyes ultimately brown. The dorsal structure is not mentioned by 

 Signoret. 



The larv^ are gregarious in small companies on the under-side of 

 the leaves of the respective food-plants in the autumn, and some even 

 survive the winter. The perfect insects, abundant up to the middle 

 of jVovember, also appear in the spring and early summer. 



I think the divergencies in structure and markings, in addition to 

 Ihc widely different and exclusive food-plants of each form respectively, 

 afford sufHcient ground for distinguishing the two species, as several 

 of the best observers have done, as noted above. 



153, Lewisham Eoad, S.E. : 



November loth, 1891. 



Postscript, November 2Gth. — On the 19th inst. I received from 

 Mr. C. W. Dale, Glanvilles AVootton, Dorset, pieces of cabbage leaves 

 to which when they were sent off on the 17th inst. were attached 

 several pupa; of A. hrnssicce, but during transit the imago form had 

 been developed from them. At first the wings were spotless, but the 

 characteristic spots appeared perfectly in a few days afterwards. 



On the 20th inst. I received from Dr. T. A. Chapman, Hereford, 

 some larvae of A. brassicce on leaves of kale, but they were not so much 

 as half-grown, and at that intermediate state they afforded no special 

 character. If the brood of which they were samples survive the 

 frosts of winter unharmed and become perfected, they may pose as 

 actors in the " Winter's Tale " of insect life. 



