fe 



142 The Ohio Naturalist. [Vol. IV, No. 6, 



My specimens of Amphibolips illicifoliae Bassett were too far 

 advanced to admit of sectioning, but a careful examination indi- 

 cated that the zones were well defined and that the space in the 

 pareuchj'ma zone is bridged b}' means of fibro-vascular bundles 

 as in A. inanis and H. centricola. 



The galls of Amphibolips prunus Walsh (Fig. 122) are very- 

 firm and all the zones are well defined excej^t the protective zone, 

 which is entirely absent. The parenchyma zone is very thick 

 and probably compensates for the lack of a protective zone. 

 There are very few small fibro-vascular bundles. 



Galls of Amphibolips sculpta Bassett (Fig. 123) were more 

 succulent than other specimens which I have examined. My 

 specimens were mature, but the four zones were well defined. 

 The nutritive zone was almost obliterated, due to the age of the 

 gall. The protective zone was thin and the cell walls not very 

 thick. The parenchyma zone was very thick and composed of 

 large, succulent cells and was probably very important in furnish- 

 ing nutriment to the larva. Near the outer surface were numer- 

 ous small fibro vascu'ar bundles. The epidermal zone was very 

 prominent and composed of small cells. 



Andricus petiolicola Bassett is one of the firmest of the leaf 

 galls. It is formed either on the petiole or mid-rib and is com- 

 po.sed of very small, firm cells (Fig. 124). The four zones are 

 well defined, but the protective zone is very thin and the cell 

 walls but very little thicker than in the neighboring cells The 

 parenchyma zone is very thick, composed of very small cells with 

 no intercellular spaces, but with many la3'ers of long fibrous cells. 



The galls of Acraspis erinacei Walsh (Fig. 125) are very con- 

 spicuous. The galls are always developed on the mid-rib of the 

 leaf, but contain no fibro-vascular bundles. The nutritive zone 

 is thick and very rich in protoplasm. The protective zone is 

 also thick and graduall}- merges into the parenchyma zone, which 

 is also thick. The epidermal zone is ver)' irregular and is covered 

 with numerous unicellular trichomes. 



The galls of Biorhiza forticornis Walsh are fig-shaped and the 

 larval chamber instead of being suspended in the center of the 

 gall, as is many others, is placed at the apex (Fig. 126a) and the 

 space between the protective and parenchyma zones, or rather in 

 tlie parcnchynia zone, extends Jess than half way round the larval 

 chamber. My specimens were mature and I was unable to make 

 a careful study of the nutritive and protective zones. However, 

 the nutritive zone appeared to be relatively thicker, while the 

 protective zone was thin and merged gradually into the paren- 

 chyma zone (Fig. 126b). The parenchyma zone was thick and 

 composed of large c^lls (Fig. 126c). Considerably more of this 

 zone remained attached to the ])rotective zone than is the case 

 with most galls where this .separation occurs. The cavity formed 



