VniPAROUS BUTTERFLIES. 238 



Viviparous Butterflies. 



By Dr. T. A. CHAPMAN, F.Z.S., F.E.S. 



In the last part of the llarae Soc. KnUntioloiiicae Ruasicae is a paper 

 by Herr N. J. Kusnezov, unfortunately in Russian, but with a copious 

 explanatory note in English, in which the author records that fully- 

 developed larvfe may be found in the bodies of female butterflies. 

 The species he notes are 21 species of Colias, 7 of Eucldo'c, 1 of Zajris, 

 and 1 of Ijeptidia. 



The larvfe were not, however, found in the bodies of living butter- 

 flies, but by maceration of the bodies of preserved specimens. This is 

 clearly a matter worth further investigation. 



We are unacquainted with any record of a butterfly having " laid " 

 a larva, or even an egg with a larva in any state of development 

 contained in it. 



There is, however, a fact often observed both by Mr. Tutt and 

 myself, and I think reported somewhere by one or both of us, that 

 many butterflies are found after death to have an egg ready to extrude 

 in the ovipositor, and from such an egg more than once a larva has 

 hatched under my observation. We have observed this most frequently 

 in the genus Erebia, chiefly because Erebias are often difficult to induce 

 to lay eggs, and often die w^ithout doing so, and an attempt to obtain 

 an egg for examination from the dead butterfly has revealed the fact 

 of one egg being ready for extrusion ; very rarely is there another 

 behind it. Everyone has observed how many moths after being 

 killed, but with the abdomen still more or less active, will lay a 

 number of eggs, without, of course, the usual incentives of foodplant 

 under proper conditions, etc. These butterflies seem to be in much 

 the same case. The desire to lay takes effect after the butterfly is 

 dead, and when no proper control exists over the still living abdominal 

 organs, and in these the result is not a complete result as in the 

 moths cited, but the egg remains in the ovipositor. It has, however, 

 passed the spermathecal orifice and is fertilised. 



As an explanation of Herr Kusnezov's remarkable observation, I 

 think it highly probable that in the species he has examined precisely 

 the same process is gone through as in the Erebias. An egg is 

 advanced past the spermathecal orifice and remains unextruded. 



Herr Kusnezov gives drawings (and very good ones) of his 

 preparations, showing one larva only in each instance, doubled up in 

 what is almost certainty the eggshell, lying in the tube immediately 

 behind the opening of ovipositor. Herr Kusnezov calls the place 

 where it lies an " uterus," but clearly there is here no expansion of 

 the tube, the egg fills it up precisely as it must do w^hen it passes 

 this spot in ordinary oviposition. The author does not note the egg- 

 shell, but this is extremely transparent in these Coliads, etc., and 

 would probably be invisible in his preparations. 



The remarkable point, then, in Herr Kusnezov's observations is, 

 that these fertilised, but just not-laid eggs, can undergo development 

 in this incarcerated position, just as if they were external. It is not 

 quite parallel wdth any case of actual viviparity, since no actual laying 

 of the developed egg takes place. Nevertheless, it is not without some 

 analogy with those MnachJae that are unable to retain the eggs in the 

 oviduct, but pass them to a quite homologous place, to wbei'e these eggs 



Septkmiser, 1911. 



