RELATIONSHIP BETWEEN LARVAL AND IMAGINAL LEGS OF LEPIDOPTERA. 143 



So far back as 1894, however, J. Goniii published a most vakiable 

 paper on the metamorphosis of lepidoptera in the Bulletin de la Societt' 

 Vancloise rte Sciences Natarelles, in which, amongst a most excellent 

 series of observations on the development of the appendages of Fierifi 

 hrassicae, for nearly all of which I have nothing but praise and agree- 

 ment, he adopts with regard to the legs the second answer, viz., that 

 the imaginal legs entirely originate from imaginal discs Avithin the 

 body of the larva. Or he may, indeed, be understood to say that the 

 imaginal tarsus arises from the larval leg, and some of his expressions 

 imply that he regards the three joints of the larval leg, not as being 

 respectively femur, tibia, and tarsus, but as being actually three 

 joints of a tarsus, the representation of tibia and upwards being within 

 the larval body. 



The question is thus expressed by Gonin [Bull. Soc. Vaud., vol. 

 XXX., 94), that Reaumur has been misrepresented, and that his actual 

 words are, that he cut ofi" " more than the half of three of the true 

 legs," and found that the chrysalid had "'the three legs of the side 

 shorter than the corresponding limbs of the other side," and that a 

 larva experimented on at a younger stage showed a fresh three limbs 

 in the pupa, but " atrophied," that is to say not entirely absent, and 

 he criticises Kiinckelfor saying that it is clear that " Reaumur, having 

 completely cut off one of the true legs in some caterpillars, proved that 

 the butterfly that emerged was without the corresponding appendage," 

 and says that Newport denied this disappearance of the legs, and 

 regarded the limb as partially regenerated. He then goes on to 

 describe the state of matters at the date of the change to pupa, when 

 the greater part of the leg has so far assumed its imaginal character, 

 and increased in size, as to have left the larval leg, and to be pressed 

 together at its base within the larval skin, leaving only a portion in 

 the larval leg roughly corresponding to the tarsus, and, though he 

 seems to have a good grip of the processes by which the imaginal leg 

 arises, he appears in a fashion curiously illogical, considering his 

 actual knowledge, to believe that the condition at this date, i.e., the 

 moment preceding the moult to pupa, represents the true relations of 

 the larval to the pupal (or imaginal) leg, viz., that the imaginal leg 

 arises from larval structures situated where he finds it at this late 

 period, when it has really by growth left its confined quarters in the 

 larval leg, and that the larval leg corresponds to the extremity (say 

 tarsus) only of the imaginal limb, and that the rest exists in the larva 

 merely as an imaginal disc not within the larval leg, hut in the body 

 of the larva at its base. 



Newport's experiments, fully recorded in the Pkilosophical Tram- 

 actions for 1844, relate to Aijlais urticae, and, properly interpreted, 

 seem to render Gonin's position untenable, whilst the results correspond 

 entirely with those of the experiments I made last year ; he brings out 

 a point with which I did not meet frequently enough to note it 

 definitely, and that is, that removal of a portion only of the leg results 

 in the tarsus being reproduced in an incomplete state, that is with less 

 than five joints. His observations on the reproduction of spines and 

 spurs do not quite accord with mine, but this also seems to have 

 occurred in the case of partial removal. Newport's experiments were 

 made with a view to learn whether regeneration of amputated parts 

 occurred in lepidoptera ; mine were chiefly with a view to test Gonin's 



