PLANT-LICE. 265 



usually they are quite black ; the male is black and winged ; 

 the young dark-grey to black ; and the pupse slaty-grey, with 

 black wing-cases and white spots and patches on the black 

 abdomen. They are also found on mangolds, poppies, hops, 

 chamomile, euonymus, docks, &c., from which they have taken 

 various specific names, having been supposed to be distinct 

 species. This aphis winters on docks and euonymus, then flies 

 to the beans and poppies, and later to mangolds and other 

 plants. 



The attack of this " louse " can easily be checked, if taken 

 in time, by picking off the infested tops of beans and putting 

 them carefully into a pail of lime, so as to kill them before 

 they spread low down. Many plant-lice, like the above, have 

 several food-plants. 



The Hop Louse {P/iorodon liumuli). 



The Hop Aphis {Phorodon humuli) first makes its appearance 

 on the hops as a winged viviparous female, the so-called "fly.'' 

 This takes place from the middle of May on into June. The 

 " fly " settle on the top growths, and at once commence to 

 produce living young, small pallid larvse, spoken of as "lice" 

 or "nits." These grow into the wingless viviparous females, 

 which continue to produce living young for several generations. 

 Now and again a winged brood has been known to appear in 

 summer on the hops, and these fly to other hops and produce 

 similar lice, but this is rare. In September the Hop Aphis all 

 become winged, and these fly to the damsons, sloes, and some 

 plums, where a sexual generation of males and females is pro- 

 duced, the ovigerous females laying eggs in the axils of the 

 buds. These hatch out in spring and feed on the foliage of the 

 prunes, and late in May produce a winged viviparous brood, 

 which fly off to the hops. Green apterous viviparous lice have 

 been found on hops (Ormerod) previous to the advent of "fly," 

 but the part they play has not been found out. They have 



