260 PARTHENOGENESIS VII 



Of the fourth and fifth chapters, treating of 

 Parthenogenesis in the Lepidoptera, Psyche helix, 

 Solenobia triquetrella and S. lichenella, we have not 

 space to speak in detail. The same intimate inquiry, 

 and the same very necessary prodigality in the amount 

 of material subjected to experiment, which we noted 

 above as to Polistes, characterise Professor Siebold's 

 treatment of these cases. The parthenogenesis in these 

 cases produces female broods, and though the male 

 of Psyche helix has been discovered since Siebold's 

 former researches on this moth, his conclusion is by 

 no means invalidated, for the males are excessively 

 rare. They were first discovered by Glaus, of Mar- 

 burg, who has indicated characters by which future 

 observers may distinguish the sex of the caterpillars. 

 Out of many hundreds of broods reared by Siebold, 

 taken in various places, ranging from the Baltic to 

 the plains of Lombardy, only once did he obtain 

 males. There appear to be thus broods which are 

 entirely female, and broods which are of mixed sexes. 

 The conditions under which the male sex makes its 

 appearance are not yet ascertained. It is exceedingly 

 desirable that those who may be fortunate enough to 

 come across a mixed brood, should make experiments 

 to ascertain if all the eggs which are fertilised produce 

 males. The females of the purely female broods are 

 completely developed in every respect, having perfect 

 copulatory organs, and the egg is furnished with a 

 micropyle ; therefore, as Siebold maintains, they must 

 not be called pseudova. It should be mentioned 

 that the inquiries necessary to establish the identity 



