12 MR. H. J. ELWES ON THE GENUS I'AKNASSIVS. [Jail. 19, 



torpid without flving ; that the duration of tiie act is from 3| 

 to 6^ hours, but the poucli is developed in a iiiucli shorter time, 

 thirty minutes in one case sufficing to make it visihle to the naked 

 eve. ' But my observations of P. mnemosyne make it evident that 

 cither that species differs from P. apollo in this respect, or that 

 instances of imperfect coj)ulation, not followed by the appearance cf 

 a pouch, niHV occur. 



Mr. Thomson also proves : —That eggs may be and are sometimes 

 laid before the completion of the act, and that they may be laid by 

 pouchless females ol' P. apollo, as I found was also the case with 

 P. i/inemospie. That laying continues for several days at intervals, 

 the life of the female extending to at least a week, whilst the males 

 appear completely exhausted by the act of copulation, and die in one 

 or two days after it without flying much, tliough they remain lively 

 and stronsr for several days before the act takes place. No attemj)! 

 was made bv virgin males ol)served by Mr. Thomson to mate with an 

 already mated female, but my own observations in nature show that 

 this is not the case in a mUural state. Tiie date ot emergence from 

 the pupa is usually two or three days earlier in the male than the 

 female, and the proportion ui' males nut much greater than of females. 

 But in a wild state the proportion of males of both P. apollo and 

 P. (lelius always seems to be much greater ; and from tiic compara- 

 tive rarity of the females in almost all the species of ti>e P. apollo 

 group this seems to be the case in other countries. But in the 

 P. mnemosyne and P. delphius groups females, though occurring 

 somewhat later, seem usually to be nearly as abundant as males. 



Notes OH the Copulation of Parnassius apollo. 

 By Arthur Thomson. 



"On the 18th of June, 1885, I received forty pups& of Parnassius 

 apollo, which had been sent to the Gardens by order of Mr. H. J. 

 Elwes, F.Z.S., for the purpose of watching the perfect insects when 

 copulating, and to endeavour, as far as possible, to throw some 

 light upon the development of the ' horny pouch ' with which the 

 female is provided after copulation. 



" How far I have been successful I must leave others to judge, but 

 1 wish to say that the fact of the female Parnassius developing 

 such a ' pouch ' after emerging from the chrysalis was quite new 

 to me, so that I had no preconceived ideas upon the subject, and I 

 have noted the facts just as they occiu'red. 



" I first had a large gauze cage made, and placed in it six plants of 

 Sedum telephium, the food of this species, and put in the insects 

 as soon as they were ready, after emerging from the pupae. 



" The first and second copulations took place on June 27 ; the 

 first pairing lasted from 11. 10 a.m. to 2.25 p.m. =3 hours 15 minutes, 

 and the second pairing lasted from 1 1.30 a.m. to 3.0 p.m. =3 hours 

 30 minutes. The ' pouches ' in each case were perfectiv developed, 

 and the females began to deposit their eggs upon the gauze within 

 five minutes of their separation from the males. 



