APPENDIX I. 



Cynips Kollari\ Hartig. 



Gall. Size i'5-3 cm. in diameter, spherical, with a well- 

 marked base of attachment at one pole, and a small bifid 

 apex at the other ; beneath this is a linear scar, and around 

 it a circle of warty elevations. 



The galls may be solitary, or two or more together on the 

 same bud ; and each is situated in the axil of a leaf, or several 

 may be found crowded together on a terminal bud, in which 

 case the internodes have been suppressed. The gall contains 

 a central elipsoidal larva chamber, which retains its shape 

 even when the gall itself is compressed and flattened by the 

 growing shoot. The gall appears in June, is golden yellow 

 if grown in the shade, and green if exposed ; it matures in 

 September, and becomes brown as the outer layers dry. In 

 this state it may hang on dead branches for three or four 

 years, but the growth of living wood detaches it sooner. 

 If a transverse section of a young gall, 3 mm. in thickness, 

 be made at the end of June, it will be found, according to 

 Beyerinck, to exhibit the following structure : a larva chamber 

 surrounded by (i) a thin la^^er of primary nutritive tissue, 

 (2) a thin layer of cells containing crystals, (3) a thin layer 

 of primary starch cells, (4) the layers of the cambium ring, 

 (5) a thick layer of large cells rich in tannin and traversed 

 by vascular bundles, (6) a layer of small meristematic cells, 

 (7) colourless hypodermal cells, (8) epidermis with uni- 

 cellular hairs containing red pigment in their cell contents. 

 In the middle of July the epidermis is thrown off, leaving 



^ Mistaken by Marshall and others for Cynips lignicola, Htg., which 

 is not a British species. 



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