268 The Ohio Naturalist. [Vol. II, No. 7, 



of this paper. The parenchyma is divided into two very distinct 

 zones, the larval chamber occupying the lower part of the inner 

 zone. The inner zone cells have much thinner walls than those 

 of the outer cells. Surrounding the larval chamber is a zone of 

 cells which stain very deeply and probably furnish nourishment 

 to the larva. The epidermal cells are small. 



Callirhytis tumijica O. S. (Fig. 26 a. b.) is a small, fleshy, solid 

 gall projecting on both sides of the leaf and resembles N. irregu- 

 laris (Fig. 25), except that it is a little larger, does not have so 

 many larval chambers and is smooth. Lt presents the simplest 

 characters studied, showing the characteristic small, more or less 

 cubical epithelial cells, the lack of differentiation into palisade 

 and mesophyll, and the two zones. The outer zone is very thick 

 and is in contact with the inner zone. The inner zone is narrow 

 and lies near the large larval chamber. At the point of union of 

 the two zones the cells are very small. The outer zone can be 

 readily subdivided into epidermis and parenchyma, but the inner 

 zone cannot be subdivided into two sub- zones unless we consider 

 the layer of small cells as the protective sub-zone. However, 

 this sub-zone of small cells does not possess the sclerenchyma 

 character described by Fockeu for the Cynipidae galls. 



Holcaspis centricola O. S. (Fig. 27 a. b. c. ) is a large, spherical 

 gall projecting both above and below the leaf. In this we have 

 the two zones, but each retaining the characters previously 

 described ; the cells of the inner zone, however, being smaller 

 than in C. tumifica. The epidermal cells have thicker walls than 

 in any other Cynipidae gall examined. The two zones are con- 

 nected by fibro-vascular bundles. In this the four zones of 

 Fockeu are quite well defined : The outer zone forming the very 

 distinct epidermis and parenchyma ; the inner zone showing a 

 fairly well defined protective and nutritive part. 



Auipliibolips ina)iis O. S. (Fig. 28 a. b. ) shows a very striking 

 resemblance to H. centricola (Fig. 27), except that it is much 

 larger. The epidermal cells do not have such thick walls as in 

 H. centricola and are much longer and narrower. The inner zone 

 is readily subdivided into the protective and nutritive sub-zones 

 described by Fockeu. The inner or nutritive sub-zone is made 

 up of thin-walled cells with prominent nuclei, the outer or pro- 

 tective sub-zone of sclerenchyma cells. The connection between 

 the two main zones is by means of fibro-vascular bundles, the 

 same as in H, centricola. 



Dryophanta palustris O. S. (Fig. 29 a. b. c. ) presents a condi- 

 tion very similar to the two preceding galls, H. centricola (Fig. 

 27) and A. inanis (Fig. 28), except that the fibro-vascular bundle 

 connection between the two zones is not present ; the inner zone 

 containing the larva forms a sphere which is free in the large 

 chamber formed by the outer zone. 



