EELATIONSHIP BETWEEN LARVAL AND niAOINAL LEGS OF LEPIDOPTEKA. 177 



The Relationship between the Larval and Intaginal Legs of 



Lepidoptera^'^ {(ritJt Plate). 



By T. A. CHAPMAN, M.D., F.Z.S., P.E.S. 

 [L'oitchidcd from p. 145.) 



Before further discussing the general question, we may look at some 

 more of the specimens. We may take that represented in plate vi., fig. 2 

 next. Here the amputated larval limb is replaced by an amorphous nodule 

 of considerable size. The basal structures seem to be fairly intact, and 

 on Gonin's theory ought to have supplied us with a leg, but the imago 

 has no leg at all beyond the trochanter and a round nodule, which 

 W'C may call the femur. I do not know at what date this specimen 

 was operated on, but I believe immediately on entering the last moult. 

 I always operated immediately after a moult so as to give plenty of 

 time for healing to take place before the next moult. In all my 

 specimens the trochanter is present in fairly normal condition, showing 

 that in amputating the leg I interfered with the femur and all beyond, 

 but not with the trochanter and coxa, which are not represented in the 

 larval leg. 



In plate vi., lig. 8, the larval parts show that the right leg 

 has been interfered Avith as well as the left. It is regenerated to much 

 the same stage as the left leg was in fig 1, and the imaginal 

 leg is correspondingly well developed, though very probably smaller 

 than the original leg would have been ; but on the left side we have a 

 stump that results from injury during the last larval stage, there are 

 some remains of the first larval joint, crushed and twisted, and 

 attached to it a black mass of dried crust, such as resulted from the 

 immediate closing and scabbing of the wound. No regeneration could 

 take place during larval life, and what did take place at the pupal 

 moult appears to have occurred, not from the base of the leg, but from 

 the crushed remains of the first larval joint. We have in consequence 

 a very small representative of the imaginal leg, a complete trochanter, a 

 femur half the length of that of the other side, a tibia to a still smaller 

 scale, but still showing the tibial spurs, the tarsus cannot be said to 

 •have more than one joint, but that carries the claws, very small but 

 fairly well developed. In this specimen the whole larval injury is 

 concentrated on the first joint, the base being uninjured, therefore if 

 the imaginal leg originated in this base, independently of the larval 

 leg, we ought to have had a limb perfect as to its femur and tibia at 

 any rate, even if we choose to accept the view of Gonin that the larval 

 leg represents the tarsus. 



In plate vi., fig. 4, we have an instance in wdiich I failed to 

 demonstrate the condition of the larval leg, it was, at any rate, much 

 damaged and difficult to recognise, but some minute trace of a cicatrix 

 of larval leg probably existed. In the imago we have a,n example, the 

 only one that seems tolerably free from doubt, of a modified trochanter. 

 The femur and tibia are represented by very amorphous pieces, not 

 united in a normal manner, the tibia, however, showing spurs, whilst 

 the tarsus is in one piece, with indications of possible division into 

 two or three joints and of the terminal hooks. The whole appendage, 

 however, is very small and crippled, clearly a very abortive attempt 

 at regeneration, and in no Avise a normal, or any way near a normal, 

 attempt to produce a limb from the usual centre for its development. 



* Read before the South London Entomological and Natural History Society. 



