1897- WASPS AND WEISMANN. 49 



season differ from the variable conditions which obtained in pre-social 

 ancestors; that these newer conditions constitute a constant modifying 

 influence on the germ-plasm, which has thus acquired a new physico- 

 chemical constitution. The ova that give rise to workers contain this 

 same modified germ-plasm, but the resulting larvae are reared under 

 conditions different from those which have now, in the course of ages, 

 become normal to the queens. The germ-plasm is therefore under new 

 conditions, and does not follow its normal course, but gives rise to 

 imperfectly developed forms (workers). As the conditions more and 

 more nearly approach those habitual to queen-ova and queen-larvae, 

 so does the resulting imago more and more nearly attain the perfect 

 form. All cases of dimorphism and polymorphism among social 

 insects with sterile forms are capable of being similarly explained. 

 These conditions, once reached, are maintained by natural selection. 



In a second paper, " Observations sur les Polistes" [Bull. Soc. Zool. 

 France, vol. xxi., pp. 15-21, 1896), Dr. Marchal points out the habit 

 of Polistes of storing small quantities of honey temporarily ; also that 

 the hexagonal form of the cell is not due to instinct, but to 

 compression, the first part of the cell being cylindrical. 



Dr. Marchal is to be congratulated on having brought together 

 by his own industry a number of valuable observations, and on 

 furnishing a sound explanation of the main problem before him. 



Oswald H. Latter. 

 Charterhouse, Godalming. 



