MOEPHOLOGY OF THE LEP1DOPTEEA. 151 



devoted a paper to the order in his researches on the female genital armature of the 

 Insecta. Herold has treated of the development of the organs in both the male and 

 female of Pleris brassicce, and Suckow has investigated in a similar way Dendrolimus 

 pini. Bessels's paper in the ' Zeitschrift fur wiss. Zool.' xvii. 1867, deals solely with the 

 testes and ovaries, their development, and the larval ducts in connection with them *. 



The conclusions come to by de Lacaze-Duthiers (Annales des Sci. Nat. (3), xix. 1853) 

 may be shortly summarized to the following effect : — First, the aperture of the bursa 

 copulatrix is in connection with the seventh abdominal sternum, and is a peculiarity of 

 the Lepidoptera not met with elsewhere among Insecta. Secondly, the oviducal aperture 

 is in the eighth somite, the normal position among Insecta ; and its proximity to the 

 anus is to be explained by the loss of the somites (ninth, tenth, and eleventh) which 

 very commonly intervene between them. Thirdly, the abdomen is composed of eight 

 somites ; in the imago it appears, however, to consist in some instances of nine, even 

 where another species of the same genus has but eight. The explanation is that a 

 delicate lamella may be intercalated between the thorax and the first abdominal somite. 

 The latter, in this case, is connected to the thorax by two processes, one on either side 

 the lamella in question. 



All these conclusions appear to be, I regret to say, incorrect. Their incorrectness 

 may be deduced by reference to PI. XVI. figs. 21, 22, 23, and 21, which represent 

 the abdomen of the caterpillar, of the newly formed pupa, of the chrysalid more than 

 one day old, and of the imago, of Vanessa Io. And the figures given not only display 

 the somites of the abdomen, but, as they are drawn to the same scale, they show another 

 point, the change of shape and size undergone by this part of the body in the passage 

 from the larval to the imaginal state. It is a change often overlooked, and the only 

 writer who has lately drawn attention to it is Graber, in his work ' Die Insekten ' 

 (Naturkrafte Series, xxii, 1877, pp. 513, 514) ; but his figures are small and diagram- 

 matic f. 



The older authorities on Entomology assign nine somites to the abdomen of the 

 caterpillar. Packard has drawn attention to the fact that ten is the usual number 

 (American Naturalist, xix. 1885, pp. 307, 308). This was the number found by 

 Kowalewsky in the embryo of Smerinthus populi, all ten somites bearing feet (Mem. 

 Acad. Imp. St. Petersbourg (7), xvi. 1871, p. 53, Taf. xii. figs. 8 and 10); but I note in 

 an abstract of Tichomiroff "s Russian paper on the development of Bombyx mori that he 

 found eleven abdominal somites in the embryo of this moth, all provided with feet save 

 the first (Naples Jahresberichte, 1882, Hexapoda, p. 112) %. The first eight abdominal 



* Cholodkowsky has figured the genitalia in a young stage of Abraxias (Zerene) grossulariata (Zeitschrift f. wiss. 

 Zool. xlii. T. xix. fig. 2) : and Emerton has published some notes on the changes in the internal organs of the pupa 

 of the Milk-weed Butterfly (Anosia plexippus) in the ' Proceedings of the Boston Soc. Nat. Hist.' xxiii. pt. 4, 1888. 

 But neither of tbem advances our knowledge of the subject in the least, beyond what was stated by Herold. 



t For the remarkable diminution of weight which occurs in the pupa, see Poulton, ' Trans. Entom. Soc' 188b', 

 pp. 170-179, and Urech, 'Zool. Anzeiger,' xi. 1888, p. 205 et seqq. 



$ In the embryo of Ganteropacha quercifolia, Graber found the abdominal segments at first devoid of appendages. 

 When the latter appear they develop only on those sogments in which they persist in the adult. He therefore 

 considers them as secondary appendages (Morph. Jahrbuch, xiii. 1888, pp. 009, 010). 



SECOND SERIES. — ZOOLOGY, VOL. V. 24 



