36o 
HARRY R. ROSEN 
30. Von Schrenk, H. R. Intumescences as a Result of Chemical Stimulation. 
Rep. Mo. Bot. Card. 1905, 125. 
31. Weidel, F. Beitrage zur Entwicklungsgeschichte und vergleichenden Anatomic 
der Cynipidengallen der Eiche. Flora 102: 279. 191 1. 
DESCRIPTION OF PLATES XIV AND XV 
All the figures are microphotographs taken with various Leitz and Zeiss objec- 
tives and eyepieces. 
Fig. I. A cross section of an embryonic bud leaf 24 hours after insect attack 
showing the formation of hairs on the upper and lower leaf surfaces. On the upper 
surface the hairs are produced only at the sides of the insect. Magnified 102 X. 
Fig. 2. A longitudinal section of a primary vein of a bud leaf. The insect is 
partially withdrawn from her normal position, but the end of her proboscis is still 
projected into the upper part of the vein. The beginning of hair formation on the 
upper surface of leaf and vein may be seen on both sides of the insect. Magnified 
127.5 X. 
Fig. 3. A cross section through the center of a three to four day old gall. 
Showing proboscis protruding through the entire width of the leaf, and showing the 
narrowness of the gall where the proboscis is working. Magnified 119 X. 
Fig. 4. Ahigher magnification of the central part of Fig. 3. Magnified 212.5 X. 
Fig. 5. A cross section of a mature gall showing among other things bent 
parenchyma cells. Magnified 14.5 X. 
Fig. 6. A cross section near the center of a mature gall showing the mouth of 
the gall, the scattering of the vascular elements, etc. 
Fig, 7. A cross section of three layers of cells immediately below the insect 
in a three to four day old gall. The thickening and dissolution of the cell walls, 
giving the appearance of a reticulate structure of tracheae is shown. Magnified 
498 X. 
Fig. 8. A cross section through a mature gall showing the nutritive zone, 
nymphs and eggs in the cavity, etc. Magnified 14 X. 
Fig. 9. A cross section of an embryonic bud leaf, showing the first signs of 
gall formation, the proboscis protruding from the upper epidermis, the narrowness 
of the leaf at this point and the beginning of hair formation at the sides of the insect. 
Magnified 127 X. 
Fig. 10. A cross section of an intumescence, produced on a cabbage leaf by a 
spray of ammonium copper carbonate. Magnified 53 X. 
