208 



Forty-fifth Report on the State Museum. 



The iasect, deserting the hop yards in the autumu, passes to plum 

 trees, on the smaller twigs of which its eggs 

 are laid and survive the winter. Hatching 

 in the early spring [and producing the 

 " stem-mother," shown in Figure 47], three 

 broods are developed on the plum, the third 

 brood being winged. This brood at once 

 takes wing, deserts the plum trees, and flies 

 to the hop yards. This flight takes place 

 in the month of May — in England it has 

 been noticed on the 28th of May. 

 The precise time would, of course, vary 

 with the temperature of different seasons, 

 Fig. 47. — The hop-vine aphis, but could be ascertained by a careful ex- 



Phorodon HujruLi, the stem- . /. i i i -i •- 



mother, enlaigred; head and aminatlOU of the hop liSVCS CiaiiV at about 



antenna still more enlarged. 



(From Insect Life.) the usual time for its appearance. 



When to Attack the Aphis. 

 The winged aphides [the " migrants," shown in Figure 48] would be 

 found at first on the upper leaves of the outer rotes of plants in the 

 yard. This is the time, without any delay, to commence operations 



FiQ. 48.— The hop-vine aphis, Phorodo.v hdmuli, migrant from plum, of the third genera- 

 tion, enlarged; head still more enlarged, (^toxsi Insect Life.) 



against them. They should be killed, and thereby prevent the enor- 

 mous progeny to which they would give rise in the nine rapidly suc- 

 ceeding generations said to have been observed on the hop -plants. 

 This multiplication, in favorable seasons, is simply appalling — almost 

 incredible, but it need not be permitted. 



It may be prevented by killing the plum-tree migrating brood while 

 upon the outer rotes of the yards. 



