132 THE entomologist's record, 



indeed very conceivably liave existed at some time or place as a pure 

 race, and would have been quite parallel to the many instances with 

 which we are familiar, of winter and summer (or spring and autumn) 

 broods. 



This conclusion is assisted by the further fact, that the later broods 

 showed gi'eat variation in the Normals, as though they were so crossed 

 with Laggards and Forwards, that there were comparatively few that 

 did not partake more or less of the characters of one or other of these 

 forms, whilst the converse of this is strikingly illustrated in the brood 

 reared from profound hybernators, in which there appeared among 530 

 larvfe, only one Forward and no Laggards. 



Pedigree breeding of caia obtained from the extreme northern limits 

 of its distribution, as well as from the southern, to jjut this conclusion 

 to a further test Avould be of much interest, and might throw consider- 

 able light on the action of climate. Especiall}^ it might in some degree 

 elucidate such facts as that caia, through many successive Normal 

 broods, can perpetuate the capacity to take on a double brooded habit, 

 with a rapid feeding summer brood and a winter brood hybernating as 

 larvse. 



The conclusions actually ascertained or suggested by the experiments 

 which are the subject of this paper, appear to be : — 1. That the larva 

 of caia presents three types, each with subsidiary varieties. 2. That 

 each of these types, and indeed each subsidiary variety, is characterised 

 by a series of moults, a succession of plumage, and habits as to hyber- 

 nation, in which it differs from the others. 3. That caia, as we meet 

 with it, may be regarded as a mongrel race, consisting of these three 

 types closely mixed and intercrossed, but capalile of separation by 

 appropriate breeding and selection, or more probably of two races, one 

 with hybernating larvae and a single brood annually, the other, consist- 

 ing of an alternating summer and winter form. 4. That though these 

 two races may conceivably, under certain climatic conditions, have 

 existed as separate and pure races, (they may do so now in some parts 

 of the world for ought I know), yet that at present in England the 

 hybernating form is most largely represented with a small intermixture 

 of the digoneutic form, which persists, as it enables the species to be 

 continued in exceptional seasons that would be destructiA'e to the 

 dominant monogoneutic type. 



DESCEIPTION OF PLATE 11. 



(All Figures of Larvae are amplified two diameters.) 



Fig. 1. Laggard of 2nd brood, hybernating in 8th skin. 



Fig. 2. Laggard of 4th brood, in 4th skin. 



Fig. 3. Laggard of 2nd Ijrood, hybernating in 7th skin. 



Fig. 4. Normal, hybernating in 5th skin. 



Fig. 5. Normal, hybernating in Gth skin ; large ca/a-like form. 



Fig. 6. Dorsal view of anal armature of caia pupa, x 6 diameters. 



Fig. 7. Lateral view of anal armature of caia pupa, x 6 diameters. 



NOTES ON PLATE IL 



Li Plate II, Fig. 1, we have a form that is very much the same as 

 a Normal hyljcrnator, and the figure gives, perhaps, a Ijetter idea of a 

 Normal hybernator than does fig. 4, taken from a Normal hybernating 



