PARTHENOGENESIS IN THE ANIMAL KINGDOM. 245 



Bomhijx mori, aud furuislies various proofs. He also observed the lay- 

 ing of uuimpregiiated eggs by other butterflies, which are hatched if 

 they belong- to the first geueratiou of the year, but never survive the 

 winter. 



Jourdau* also observed true parthenogenesis in the silk- worm. 



At the forty-seventh meeting of Swiss naturalists at Samaden, de 

 Filippi reported that healthy caterpillars were hatched from the eggs of 

 the Japanese silk-butterfly, although they had certainly not been fe- 

 cundated, and mentioned a similar observation of Curtis on the Bombi/x 

 atlas. 



In certain species of coccides Leuckart (p. 30) also found partheno- 

 genetical generation. In the Lecanlum and A.spidiotusj for instance, the 

 eggs are developed in tubes without being previously impregnated, and 

 the spermatozoa are entirely wanting. In the genus Chennes {Ch. ahietis, 

 Kaltenb., Ch. lai-ids, IlarUnr/, Ch.iyicew^ Fat;:;!)., PJiyUowra cocclnea., Ileydcn) 

 of the plant-lice, having, according to Leuckart,! both a winter and a 

 winged summer generation, which latter was erroneously taken for 

 males by Ratzeburg, reproduction proceeds by means of eggs without 

 previous impregnation. Leu(;kart examined two hundred animals, and 

 never found males but always females, and they virgins. Males do not 

 seem to exist, or if they do, parthenogenetical reproduction seems to be 

 the rule. Less accurate observations of the same kind were made by 

 Dr. Ormerod t on the Vespa hritajinica, and by Stone § on the Vesjia 

 vulgaris. 



Leuckart (pp. lOo-lOT) has furthermore established the fact that in 

 all otlier sociable Hymenoptcra, as the bumble-bee, the wasp, and the 

 ant, as well as in the bee, parthenogenesis prevails. Egg-laying work- 

 ers, which are exceptional with bees, are the rule with these animals. 

 Future researches must decide whether their progeny is always male, as 

 Huber's§ observations of bumble-bees seem to indicate. No doubt we 

 will also find parthenogenesis with many other insects, such as the ter- 

 mites and the gall-fly. In the gall-fly, a species of cynips, no nude has 

 yet been discovered, but only females. 



The experiments of Lievin aud Zenker, which demonstrated the 

 spontaneous develoiiment of the daphides, have been confirmed by J. 

 Lubbock. Millions of the females of these animals, which are scarcely 

 a line long, may be seen in summer moving about in cisterns and other 

 standing sweet waters. They multiply in ra[)idly succeeding genera- 

 tions by means of unimpregnated or summer eggs in a cavity between 



* Compt. Rend., 18G1, tome 5;{, p. 1093. 



tTroscliel's Archives, vol. 25, p. 208. Scltizoiicura seems to have only au oviparous 

 fall generation. 



I Zoologist, 1859; and Entomol. Annual for IHGO, p. 87. 



^Proceedings Entomological Society, 1859, p. 8G; Smith in Entomol. Annual for 

 1861, p. 39. 



II Transactions of Linn. Society, 1802, vol. G, p. 288. 



