24 



On a single leaflet of one of the compound leaves I counted 



84 of the pseudomorphic larvse together with seven cast 



skins of the same. 

 The question as to whether these abnormal larvfe moult is 



thus no longer in doubt. 

 The larvfe on this leaflet were, without exception, of the 



pseudomorphic (" Periphylliis") form. 



(2) The ramifications of the " nerves " in the folioles of these 



sloughs were, in some cases, clearly seen to be filled with 

 air, thus demonstrating their vascular character. 



(3) From the same leaves of Box-elder I removed 24 black n-inf/ed 



females, and deposited them in four tubes, placing six 

 aphides in each tube. Three days after, one of these tubes 

 contained a live pseudomorph. 

 This establishes the fact that both the alate and apterous black 

 females may produce the pseudomorphic larvae. 



(4) In the month of July I obtained two larvfe of the normal 



form from an isolated black apterous female. 



(5) July 22nd. On a single leaf of Acer campestre I counted on 



the upper side 269 pseudomorphic larvse and on the lower 

 side 98, making a total of 367 on the whole leaf. 



