NOTES ON BUTTERFLY PUP^, ETC. 105 



to use it in the case of pujiaj, unless one wishes to suggest that the 

 pu])al tubercle represents the larval tubercle, as is certainly the case 

 in some pupto of Tineina and others, where tlieir disposition and 

 possession of hairs is identical in larva and pupa. In the Initterflies, 

 the " ocellar tubercle" is, more prol)aI)ly tlian the reverse, not identical 

 with a larval tubercle. As to " ocellar " — the position is in front of 

 the eyes, and it no doubt serves for the protection of the eyes, as well 

 as of the rest of the head ; perhaps even more for the protection of 

 the bases of the antennte than of the eyes. But, assuming an ocellar 

 site for the nose-horns of Papilio, is it certain tliat the nose-horn of 

 Pirn's is the same structure, conjoined in the middle line ? In many 

 pupje there may be seen, between the double nose-horns, two minute 

 prominences, which are possibly those that are develoi)ed in the Pieridae. 

 These may be seen in most Vanessids, and, in such a })upa as Do- 

 ritis, where the nose-horns are so short that their existence might 

 be disputed, there are between them, two very distinct tubei'cular emi- 

 nences. The front of a butterfly pupa has, in fact, an inner and an 

 outer pair of eminences. Is it certain that the inner pair does not form 

 the " nose-horn " in some cases ? If it does, it would not properly be 

 termed " ocellar." It is perhaps of more importance to note that the 

 eyes are dorsal structures, whilst the nose-spines are ventral. 



From this original form the other families branched off. 1. Par- 

 nassiiude ; this did not progress very far beyond Papilio, and is sometimes 

 included in the Papiliouiuae. 2. Pieridae ; and along with them 

 Nymphnlidae, the latter leaving the Pieridae, Avhilst only the earliest 

 forms of the latter had been evolved. 3. Lycaenida. 



In each of these groups, the lowest forms agree Avith the primeval 

 butterfly in the movability of the otli and 6th abdominal segments, 

 but, whilst the others progressed, more or less rapidly, to forms with com- 

 plete immobility of those segments, Papilioninae stands alone, con- 

 stituting an apftarently separate family that made no further j^rogTess 

 in this direction. 



The first of these lines of development, the Parnassian, seems the 

 simplest ; an early result is Thais (figs. 3-5), which has a truly Papilionid 

 pupa, but one with certain peculiar features which it will be more in- 

 structive to return to, when we come to consider the origin of 

 Nymphalidae. 



In the second line of development, the Pierid, we find a change 

 which does not occur, so far as I know, in the pujja of any of tlie 

 Heteroceka. Pjy the development of certain dorsal tubercles at the 

 margins of the segments, (possibly due to the fusion of the anterior 

 trapezoidal tubercles of the larva), antero-posterior movement is lost, 

 only lateral movement is jjossible ; so that whilst a Papilionid pupa can 

 move its tail in any direction, that of a Pierid (figs. G-I I) can only do 

 so from side to side. The peculiar method of suspension adopted by 

 the Papilionid pupa, restricts antero-jxjsterior movement, perhaps even 

 renders it dangerous; accordingly, even in Papilio, this is less free than 

 lateral movement, and we can understand how easily it might be lost, 

 and the Pierid form originated. In the Pierids there is also a change 

 in the egg ; the hemisj^herical, smooth form gives })lace to a rallrr, 

 ribbed structure. 



Among the Pieridae further changes in the pupa occur, resulting in 

 a further loss of motility of segments ; in Pier is (tigs. 'J-lO-ll), and in 



