PLATE 18 



302 Andricus lana Fitch, oak. 



13 Eriophyes on poison ivy. 



295 Andricus lana, oak.. 



54 Chermes abietis Linn., spruce. 



287 if) Dryophanta ignota Bass., oak. 



290 (i^) Dryophanta ignota Bass., early stage, oak. 



3 Cecidomyia pini-rigidce Pack., pine. 



180 Hormomyia cratcegifolia Felt, Crataegus. 



86 (?) Hormomyia clarkei Felt, Crataegus. 



75 Euura ovum Walsh, willow. 



96 Pemphigus rhois Walsh, sumac. 



289 EcUxdemia poputella Busck, poplar. 



210 Pemphigus populicaulis Pack., poplar. 



281 Mycodiplosis populifolia Felt, poplar. 



[102] 



