6 BKITISa OAK GALLS. 



being green, is red or crimson, and from it exudes a 

 sweet sticky substance. In Druoplianta scutellaris 

 there are three distinct layers. Surrounding the 

 larva are the primitive nourishing tissues; next is a 

 thin layer of bundles of hard cells, these being sur- 

 rounded with a thick coating of palisade-like cells, 

 with a thin epidermis containing colouring matter. 



Three galls, although plurilocular in growth, are 

 widely dissimilar in the covering which surrounds the 

 cells when the galls are in perfection of growth. Aj^h. 

 railicis not only has the appearance of a truffle, but 

 when cut is very much like One ; it also resembles a 

 potato, and has the same solid but sappy consistence. 

 Although usually below ground, decay is slow. In 

 Teras terminalis the texture is looser, but contains 

 more sap in proportion; it ultimately becomes spongy, 

 and, except the cells, decays during the following 

 winter. Andricus ramull is perhaps unique. The 

 little larval cells, massed together to the number of 

 ten or twelve, are entirely concealed by a dense mass 

 of long white simple hairlets, neither the origin nor 

 the structure of wdiich appears to be known. 



A more complex structure is that of Neuroterus 

 lenticularis. When examined in September it is found 

 to consist of a central mass of cells, full of primitive 

 nourishment for the larva which occupies the centre ; 

 these the larva consumes before the gall falls. Outside 

 these cells are bundles of palisade-like cells, which are 

 surrounded with a thick layer of other cells containing 

 starch granules, and upon these the larva feeds before 

 it pupates. A thick epidermis with chlorophyll 

 granules forms the exterior, from wdiich there grows 

 numerous hairlets arranged in a stellate manner. 



Gynips Kollari is not only the most complex of British 

 galls, but also the most durable. According to Beye- 

 rinck (' Beobachtungen fiber die ersten Entwicklung- 

 sphasen einiger Cynipidengallen,' p. 142 et seq.), when 

 the gall approaches maturity the cellular tissues 

 become differentiated into eight layers : (1) The 



