94 ^f' CuRTis's Obfervaiions on AphiJa, 



It appears that the excrementitious fubftance both of this black. 

 Apb'n and the common green one cryftallizes foon after it is evacu- 

 ated at this feafon of the year; for we obferve a white fubftance on 

 the leaves where the Aphides are, and fcarcely any of the glofTy 

 honey-dew. 



At twenty minutes paft fix in the evening of May 31ft, I immerfed 

 fome black Aphides in water, with the leaves of the Evonymus europaus 

 on which they were feeding, in two feparate glafles of water, and took 

 them out at ten. All furvived the experiment. 



At twelve at noon I immerfed fome common green Aphides on goofe- 

 berry ihoots, and a black fort on Evonymus, in water; when taken 

 out at twelve at noon next day they were found every one dead. 



Tab. v. fig. I. reprefents part of a branch of the Salix viminalis 



with a number of fpecimens of the Aphis /alias. 

 fig. 2. is a female of the fame fpecies magnified, in the 



a£l of excluding its young. 



V. Remarks 



