PAIRING OF APHIDES. 237 



species accordingly, of which M. Bazin witnessed the 

 birth on the 29th of July, was secluded upon a poppy 

 leaf, and by the 7th of August it had brought forth 

 seven young ones. In similar trials with others of 

 the same species, as well as with that of the rose 

 (Aphis Rosce), the same results followed. 



M. Trembley proceeded somewhat differently, se- 

 lecting two nearly of the same age from the species 

 which feeds on the elder (Aphis Sambuci), and 

 treating them in the same way, placing each upon a 

 shoot of elder enclosed in a glass tube open at both 

 ends, one of which he plunged into water, and 

 covered the other with cotton. Although he did 

 not begin his observations till the 28th September, 

 the first produced young on the 25th, and the second 

 on the 28th November, and continued at irregular 

 intervals according to the temperature of the air. 



Trembley's breeding apparatus. 



The species selected by M. Lyonnet were those of 

 the rose and of the willow (Aphis Solids) , with 

 which the results were the same as the preceding. 



M. Reaumur in his experiments introduced the 

 stem of the plant through an aperture in a piece of 

 moist parchment which covered a glass containing 



