16 



^ 



PAPERS ON APHIDIDiE. 



The rearing; cages used were of three kinds, a cage to observe molt- 

 ing (fig. 7), one for continuous-generation series (fig. 8). and a stock 



cage (fig. 9). ' 



. The cage for the moUing observations (fig. 7) consists of a 5-inch 

 flowerpot and the ordinary lantern globe, with a muslin cover over 

 the top. A plant is potted, and a thin piece of black ])a])er is fitted 

 closely about the ])lant, the pa])er ])oing the full size of the pot. 

 Absorbent cotton, is then pushed tlown about the plant to fdl in com- 

 pletely the space between plant and paper; the cotton is then black- 

 ened with carbon ink. In this manner the grayish-white cast skins 

 of the aphides can readily be seen against the black background. 



The cage for the consecutive-generation series (fig. 8) is the same 

 as the molting cage minus the paper. 



The stock cage (fig. 9) consists of a 10-inch flowerpot and a 6-inch 

 globe. This globe is the same as the one commonly used in villages 

 for street lamps. 



All i)ots shcndd be placed in saucers and irrigated — never watered 

 from the top, as this causes the soil to become very hard and the 

 plants will not grow so well. 



ADDITIONAL COPIES o f this publication 

 Xi- may be procured from the Superintend- 

 ent OF Documents, Government Printing 

 Office, Washington , D. C. , at 6 cents per copy 



