2S2 TRANS. ST. LOUIS ACAD. SCIENCE. 



thus easily kept fresh and growing for a fortnight and upward. 

 From day to day, as the winged females were obtained from other 

 vessels prepared for the purpose with infested roots, they were 

 introduced into these jars containing living leaves. 



The results of these endeavors to supply the winged mothers 

 as nearly as possible with the natural conditions have been satis- 

 factory, and they prove that, as was surmised, the eggs are laid 

 in crevices of the ground around the base of the vine, but still 

 more often on the leaves, attached generally by one end amid 

 the natural pubescence or rather down of the under surface ; and 

 while heretofore all efforts to artificially hatch the progeny from 

 these eggs have for the most part failed, I have this year succeeded 

 in hatching them without difficulty, and present a tube with liv- 

 ing individuals and also mounted specimens for the inspection 

 of members. I have also succeeded in getting both sexes of the 

 American Oak Phylloxera and in thus completing the natural 

 history of both species. 



Though this true sexual form of vastatrix, from the winged 

 and agamous female, has never before been carefully observed 

 and described, it was nevertheless anticipated by Balbiani in his 

 studies of the European Oak Phylloxera {Phylloxera quercus 

 Fonsc.) and by myself in my studies of the American Oak spe- 

 cies {P. Riley 7).* Balbiani had also obtained what is evidently 

 the same form from eggs deposited by wingless, hypogean moth- 

 ers late in the season and after the winged mothers cease to fly.| 

 The winged females carry in the abdomen from three to five 

 and sometimes as many as eight eggs. These eggs are of two 

 sizes — the smaller, which produce males, about \ the size of the 

 larger, which produce females. As the whole organization of 

 these aerial mothers— with the stout proboscis and ample wings- 

 indicates, freedom and nourishment are needed to bring the eggs 

 to perfection and cause their proper oviposition. In confinement 

 in small vessels, where these requisites are not easily furnished, 

 the eggs are generally voided, with the death of the parent, on the 

 sides of such vessels ; and those freely laid are with the greatest 

 difficulty brought to the hatching point. Only in two instances 

 did I succeed in doing this last year. These failures in the past 



* Seventh Mo. Ent. Rep., p. 119 



t Comptes Iiendus de VAcad. des Sc, Paris, Nov. 2, 1874. 



