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XV. New light on the formation of the ahdontindl poncJi 

 in Parnassius. By Samuel H. Scuddee, F.E.S., of 

 Cambridge, Mass., United States. 



[Read November 2nd, 1892.] 



Captain Elwes, in a paper on the genus Painiassius 

 (Proc. Zool. Soc. Lond., 1886, 6—58, pi. 1—4), has 

 based his classification of the species largely on the 

 structure of the abdominal pouch of the female, and 

 given a very interesting and useful resume of what was 

 known with regard to its formation. From this, and the 

 new observations by Thomson and Howes given in his 

 paper, as well as from some notes of his own, it would 

 appear to be the general conclusion that the abdominal 

 pouch seen on the under surface of the subterminal 

 segments of the abdomen of the female of Parnassius 

 is not present when the butterfly emerges from the 

 chrysalis, but is constructed during the prolonged 

 pairing of the sexes by a secretion formed at the 

 time, and which hardens into a definite form, varying 

 according to the species. Whether this secretion pro- 

 ceeds from the body of the male or of the female, and 

 by what means it takes on its definite shape, there is 

 more variance of opinion, but the weight of testimony 

 appears to be in favour of regarding it as formed by the 

 male, and moulded upon the shape of the terminal seg- 

 ments of his abdomen. Siebold, who was the first, more 

 than forty years ago, to make scientific observations on 

 this point, believed that the secretion was poured out from 

 under the two lateral valves of the male (ergiesse sich 

 .... das gerinnende Secret unter die beiden seitlichen 

 Klappen), by which he means the expanded and pro- 

 longed side pieces of the eighth abdominal segment. 



My attention was specially directed to this matter by 

 the field observations of Mr. David Bruce in Colorado, 

 communicated to me by Mr. William H. Edwards, who 

 asked me to verify and explain the same by dissection 

 of the male abdomen. Mr. Bruce, whose interesting 



TRANS. ENT. SOC. LOND. 1892. — PART IV. (DEC.) X 



