43° The Ohio Naturalist. [Vol. Ill, No. 7, 



ABBREVIATIONS. 



ep. — epidermal zone. 



pa — parenchyma zone. 



pr. — protective zone. 



nu. — nutritive zone. 



f. V. b.—fibro- vascular bundles. 



Bud of Hicoria ovata. 



Holcaspis globulus on H. ovata. 



Andricus seminator gall and two buds on Q. alba. 



Andricus seminator gall and bud scar on Q. alba. 



Section of Andricus seminator gall on Q. alba. 



Cecidomyia gall on A. negundo. 



Pachsylla c -gemma on C. occidentalis. 



Cross section of .stem of Solidago. 



Trypeta solidaginis on Solidago. 



Gelechia gallae solidaginis on Solidago. 



Cecidomyia rigidae on Salix. 



Phytoptus quadripes on A. saccharinum. 



abnormis on T. Americanum. (Two larval chambers.) 

 " acericola on A. saccharinum. 



Petiole of Juglans nigra. (Cross section.) 

 Erineum anomalum on J. nigra. (Young gall.) 

 Erineuni anomalum on J. nigra. (Mature gall.) 

 Pemphigus ulmi-fusus on V. Americana. 

 Colopha Ulniicola on U. Americana. 

 Phylloxera carya-fallax on H. ovata. 



I. t 4 it t . 



" carya-globuli on H. ovata. 



Cross section of petiole of Populus monilifera. 



Pemphigus populi-transversus on petiole of P. monilifera. (Young gall.) 

 Same in section 



P. p.-transversus. Part of gall near opening into larval chamber. 

 P. p.-transversus. Section back of chamber and showing one fibro-vascular 



bundle of the petiole. 

 P. p.-caulis. Young gall ; ventral surface. 

 Young gall; dorsal suiface 

 " Young gall ; open. 



" Ventral surface. 



" Dorsal surface. 



" Open. 



Pachypsylla celtidis-mamma on C. occidentalis. (Young gall.) 

 P. c.-mamma. Diagram. 



Section of dorsal part. (2 and 3.) 

 " Section of ventral part. I3 and 4.) 



Cecidomyia gleditsia; on G. triacanthos. 



verrucola on T. Americana. (Young gall.) 



Callirhytis papillatiis on (j. palustris. 

 Dryophanta palustris on Q. palustris. 

 Diastrophus siminis on N. glechoma. 



" " Diagram. 



" " Nutritive and protective zones. 



" " Epidermal and parenchyma zones. 



" " Strand connecting protective and parenchyma zones. 



'■ " Nutritive zone in gall almost mature. 



