278 The Ohio Naturalist. [Vol. II, No. 7^ 



descriptions of several species inhabiting the Oak Galls of Illinois." 

 Proc. Ent. Soc. of Phil. Vol. II. No. 4. pp. 443-500. 



22. Walsh, B. D. "On Insects, Coleopterous, Hymenop- 

 terous, and Dipterous, inhabiting the Galls of certain species of 

 Willows." Proc. Ent. Soc. .of Phil. Vol. III. pp. 543-644 • 

 id. Vol. VI. pp. 223-288. 



EXPLANATION OF PLATES. 



In making the drawings, a Bausch and Eomb microscope and 

 camera lucida were used. Figs. 1-7 were made with i-inch ocular 

 and 1-5-inch objective. The diagrams of the galls were not made 

 upon a definite scale. All other drawings were made with i-inch 

 ocular and -3-inch objective. 



Abbreviations : e. — epidermis. nu. — nutritive zone, 



end. — endodermis. o. e. — outer epidermis, 

 f. — fibro-vascular bundle. p. — protective zone. 



1. c. — larval chamber. pa. — parenchyma. 



1. Cross section of leaf of Hicoria ovata. 



2. " " Salix cordata. 



3. " " Vitis vulpina. 



4. " " Ulmus americana. 



5. " " Acer saccharinum. 



6. " " Tilia americana. 



7. " " Quercus alba. 



8. a. b. Phytoptus ulmi on Ulmus americana. 



9. a. b. " abnormis on Tilia americana. 



10. a. b. " quadripes on Acer saccharinum. 



11. a. b. " acericola ^ <i 



12. Schizoneura americana on Ulmus americana. 



13. a. b. Colopha ulmicola on Ulmus americana. 



14. a. b. Pemphigus ulmi-fusus on Ulmus americana. 



15. a. b. Hormaphis Hamamelis on Hamamelis virginiana. 



16. a. b. Phylloxera carya-avena on Hicoria ovata. 



17. a. b. c. " " fallax 



18. a. b. c. " " globuli 



19. a. b. " " spinosa " " 



20. a. b. " " depressa " " 



21. a. b. " vastatrix on Vitis vulpina. 



22. a. b. c. d. Cecidomyia gleditsiae on Gleditschia triacanthos. 



23. a. b. " pilulae on Quercus alba. 



24. a. b. " verrucola on Tilia americana. 



25. a. b. Neuroterus irregularis on Quercus macrocarpa. 

 21. a. b. Callirhytis tumifica " alba. 



27. a. b. c. Holcaspis centricola " palustris. 



28. a. b. Amphibolips inanis " rubra. 



29. a. b. c. Dryophanta palustris " palustris. 



30. a. b. c. Callirhytis papillatus " sp. _ 



31. Longitudinal section of Cecidomyia Solidaginis on Solidago. 



32. " " " salicis-strobiloides on Salix cordata. 



33. Callirhytis clavula on Quercus alba. 



a. Longitudinal section. 



b. Cross section. 



c. " " of leaf from b. 



d. " " of larval chamber from b. 



Note :— P. vastatrix was also collected on V. bicolor; C. pilulae was also 

 collected on Q. rubra and Q. palustris. 



