Andricus gemmatus. 39 



of a leaf, little greenish or brown elevations about 

 I mm. high. As it happened I obtained no flies, for 

 I had overlooked the time when they emerge and had 

 allowed it to pass ; all I could vouch for was, that by 

 the beginning of August the flies had left the galls. 

 In 1878 I repeated the experiment; between April 

 23 and 28, ten buds were pricked ; and between May 

 3 and 6, twelve buds on a second oak. In June the 

 same little galls appeared, from which the flies emerged 

 at the end of July. In 1879 I made the experiment 

 for the third time with similar results. 



[The bark gall is found in September on Quercus sessiliflora, 

 Q. pedunadata and Q. pubescens. 

 Inquiline. Synergns incrassatus. 

 Parasite. Toryrnus corticts.l 



7^. Andricus gemmatus. n. sp.^ 

 Gall. These galls are small and inconspicuous, 

 scarcely 2 mm. long, and they are often overlooked 

 because their apices are frequently the only parts that 

 project. They are usually formed in the axil of a leaf, 

 near the later winter buds, and apparently spring 

 from the rudimentary bud. They are also sometimes 

 found free on the shoots. It is possible that the egg 

 is sometimes laid exactly in the axil of the later leaves, 

 and this may give the gall the appearance of growing 

 out of a little axillary bud. The gall consists of 

 a thin smooth rind which at first is green but later of 

 a brownish colour ; and it can be recognized most 

 easily by the hole through which the fly has emerged. 

 (Fig. 7^.) Neither gall nor fly has been hitherto 

 [} Andricus coriicis, sexual form, Cameron.] 



