﻿FIELD AND FOREST. 171 



One or more layers of cells distended with protoplasm, form on the 

 walls of the cavity, they incline to make little grape like masses. Ac- 

 cording to Lacaze Dutheirs this alimentary tissue is often surrounded 

 (especially in group 2 ) by a tissue filled with starch that later becomes 

 a sclerenchymatous wall. The galls are one or many chambered, de- 

 ciduous or not, and the metamorphoses are completed within the gall. 

 I am acquainted with 94 kinds in central Europe on four species of 

 oak, and not more than about 20 on other plants including two on 

 grasses, Festuca, and Psamma. 



Group I. The three kinds of tissues viz Dermatogen Peribkme and 

 Plcrom take part in the formation of the gall, the last however but 

 slightly. The gall is covered by the true epidermis, sometimes sto- 

 mate are found. To this group belong all galls not found on the oak 

 and also those of the oak which develop in the spring with the leaves 

 (except those of Andricusler terminalis) as Spathegaster apri Units on 

 the young sprouts, Spathegaster albipes, Sp. tricolor, Sp. baccarum, 

 Sp. verrucosa, Andricus curvator, A. crispator etc. all upon the leaves. 

 Farther the terminal and side galls on the buds of the oak as Cynips 

 Kollari, Aphilothrix cat lido in a which is usually terminal, also the galls 

 on the staminate flowers as in Spathegaster grossulariae ', etc. 



Group II. The female Cynips inserts her egg in the Plerom of some 

 organ either the cambium of the vascular bundles of the leaves or axes. 

 The growing gall tears the peribleme and dermatogen forming a cleft 

 from which the gall issues. The wounded vascular bundle sends off 

 branches which ramify in the gall. 



As examples we may cite most leaf galls as : Dryophanta scutellaris, 

 Dr. folii, Dr. diosa Dr. disticha, Dr. agama etc. Also JVeuroterus 

 numismatics, JV. fumipennis, JV. lenticularis, JV. lanuginosus etc. and 

 the stem galls of Aphilothrix Sieboldi, Dryocosmu's cerriphilus &c. I 

 contemplate a farther revision of the galls of the Cynipidce. 



Singular Occurrence. — -It is noted in the transactions of the 

 Botanical Society of Vienna, that a weeping willow in that city, has 

 borne staminate and pistillate flowers at the same time. 



