244 ALTERNATE GENERATION AND 



could be discovered by meaus of the microscope. He was to return 

 next morniug, and the carriage was already before the door, when he 

 appeared before the baron and asked permission to remain one day 

 longer. He stated that he had been unable to sleep on account of his 

 want of success, and that a new method had occurred to him, which he 

 desired to try.* This method succeeded perfectly, and v. Siebold very 

 frequently saw seed-filaments (thirty one times in fifty-two, and in two 

 of these cases mobile) in the interior of the bee-eggs. But these sperma- 

 tozoa were found exclusively in female eggs, and were entirely wanting 

 in the male.t We therefore owe to SiebokFs wonderful observations 

 and laborious experiments the definitive establishment of Dzierzon's 

 theory that the drone-eggs are developed parthenogenetically without 

 impregnation by the male seed. This fact, abundantly confirmed by 

 many accurate and oft-repeated investigations, and also by Leuckart's 

 valuable work,| must now be received as scientifically established. 



When parthenogeneticcil reproduction was thus undoubtedly proved 

 in bees, the above-mentioned more ancient statements were carefully 

 re-examined. In the Solenohia triquetrella and the ^olenobia Uchenella 

 belonging to the moth family, it was found that the females (which were 

 brought up from the caterpillar stage in a closed box) laid numerous 

 eggs soon after leaving the pupce, and that these eggs produced small 

 caterpillars. V. Siebold dissected such moths before and after they 

 laid their eggs, and found their ovaries constituted exactly like those 

 of other female butterllies, but not a trace of male spermatozoa could 

 be discovered.§ The eggs could not therefore be impregnated, and 

 must undergo spontaneous development. 



Of the remarkable apterous Ijutterfiy, Psyche helix, Siebold, whose cat- 

 erpillar makes a spiral bag, no one has yet been able to find the male, 

 although it has been sought for over fifteen years. And yet these fe- 

 males annually lay their eggs in the pupa envelope, which remains .be- 

 hind in the caterpillar bag, and in the fall these produce the caterpillars. 

 On dissection, true eggs with micropyle, a seed-vessel, but always with- 

 out male si)ermatozoa, and a copulating pouch are found. These pecu- 

 liarities iireclude the opinion that the psyche female is only a nurse. 



V. Siebold and Schmid furthermore succeeded repeatedly in obtain- 

 ing caterpillars from the eggs of a virgin silkworm, and from those of 

 the Smerinthus, which became pupre and emerged as perfect male and 

 female insects. 



A. Barthelemyll also confirms the existence of parthenogenesis in 



* BieuenzeitHiig, 1863, p. 222. 



t True Parthenogenesis, etc., j). 111. 



t Zur Keuutniss des Gefferations wecbselsuuil der Partbeuogenese, etc., Frankfort, 

 1858, p. 51. 



§ Also Lnckart, idem, p. 45. 



||£tudes et Cousiddrations G^nerales sur la Partli<?nog«5nese, (Aunales des Sciences 

 Natiuali's, XII. p t^OT.) 



