306 MAINE AGRICULTURAL EXPERIMENT STATION. I915. 



THE POND-LILY APHID AS A PLUM PEST.^^^ 



One of our best-known aphids common upon various water 

 plants is Rhopalosiphum nymphaeae (Linn.). This has re- 

 ceived considerable attention as a "semi-aquatic" species which 

 on account of the waxgland areas of its body appears to be 

 particularly adapted to a life in moist localities and to suffer no 

 inconvenience from contact with water while feeding on aquatic 

 plants. 



One of the most troublesome of our plum aphids in ]\Iaine 

 is a species inhabiting the shoots and the ventral surface of the 

 leaves, ordinarily without causing curl or similar deformation 

 of the leaf, but exhibiting a dangerous tendency to feed also 

 upon the young fruit itself as well as tapping the fruit stems. 



After watching this plum aphid several years and wondering 

 where its summer home might be (for it is a migratory species, 

 leaving the plum in June) it was noticed that there were appar- 

 ently no structufal characters to separate this from the common 

 pond-lily aphid, R. nymphaeae. 



In view of this the "migration test" was made this spring by 

 placing the spring migrants (alate viviparous forms) from plum 

 upon water plantain, Alisma Plantago-aquatica; arrow-head, 

 Sagittaria latifolia; and cat-tail flag, Typha latifolia; which had 

 been potted and kept under laboratory control. These three 

 plants are on the approved dietary of R. nymphaeae and the 

 plum migrants accepted them all readily, and the progeny of 

 the plum migrants are perfectly content with the habitat given 

 them. 



Thus the life cycle of the ancient aphid is found to include 

 a residence upon the plum, migrating thence to water plants for 

 the summer and returning to the plum in the fall for the depo- 

 sition of the over-wintering egg which provides for its spring 

 generations upon that tree. 



Biosteres rhagoletis Richmond, sp. n., A Parasite 

 of Rhagoletis pomonella Walsh. t 

 During the summer of 1913 the writer was engaged in study- 

 ing blueberry insects in Washington County. Maine. A maggot 



*This is an abstract of a paper with the same title, by Edith M. Patch, 

 publis'hed in Science, N. S., Vol. XLII, No. 1074, page 164, July 30, 191 5. 



tThis is an abstract of a paper with ithe same title, by William C. 

 Woods, published in The Canadian Entomologist, Vol. XLVII, pp. 293- 

 295, with 3 figures. 



