THE MONTHLY BULLETIN. 



288 



Fig. 284. — The common nematode or potato eelworm (Heterodera 

 radicicola Greef). 1, egg, magnified 200 times; 2, egg, sliowing develop- 

 ing larva within; 3, young larva, magnified 200 times; 4, same, magni- 

 fied 350 times; 5, adult female and gall, magnified 70 times; 6, same, 

 opened, showing organs of female, and eggs and young larvae as they 

 are found in the gall ; 7, head of female, greatly enlarged ; 8, part of 

 egg tube, showing forming eggs ; 9, another part of tube, with a fully 

 foi-med egg in it. a, alimentary canal ; e, egg tubes ; h, head ; o, oesopha- 

 gus ; s, spear. (Drawing by Newcomer.) 



