158 TRANSFORiMATlONS OF INSECTS. 



Tincina have that power of reproduction which dispenses with 

 the male for many generations. The maiden females of Solenobia 

 lay eggs which are fertile, and a succession of broods may occur 

 without a male ever being seen. This method is sometimes 

 called " parthenogenesis." 



The celebrated German naturalist, Von Siebold, examined into 

 this question, and his work was translated by W. S. Dallas, in 

 1857. Von Siebold collected a great number of the cases, or 

 sacs, as he calls them, of Solenobia lichcnella and Solenobia triquc- 

 trella, and to his great astonishment none but female individuals 

 came out of them, and only a single locality furnished him with a 

 couple of males. He kept these females carefully in little vessels 

 closed with glass lids, and found that they clung to their cases, 

 resting upon the outside of them. These virgin females laid eggs 

 and filled their sacs with them, and did not wait for any fertilising 

 male, for they commenced egg-laying very soon after they escaped 

 from the pupa case, or the chrysalis condition. When the 

 SolenobiiU were removed from their sacs, they had such a violent 

 impulse to lay, that they pushed their laying-tube about in search 

 of the surface of the sac, and at last let their eggs fall openly. 

 He writes : "If I had wondered at the zeal for oviposition in 

 these husbandless SolenobicB, how was I astonished when all 

 the eggs of these females, of whose virgin state I was most 

 positively convinced, gave birth to young caterpillars, which 

 looked about with the greatest assiduity in search of materials for 

 the manufacture of little sacs." He thought that this egg-laying 

 might be a similar phenomena to that of the birth of successive 

 generations of ApJiidcs from the internal budding of sexless indi- 

 viduals ; but on examining several of the Solenobia;, they proved to 

 be perfectly-developed females. A similar laying of fertile eggs 

 by a virgin of the species Psyche helix is noticed and carefully 

 explained by Von Siebold. He states : " The two species of sac- 

 bearers just mentioned are not, however, the only representatives 

 of the true parthenogenesis ; an equally striking example of the 

 virgin reproduction of a female insect is presented by Psyche 

 helix. Of this remarkable moth we are at present only certainly 

 acquainted with the female. In the caterpillar state it lives in a 

 sac which in its form resembles a sinistral (turning to the left) 



