HYMENOPTERA. TEREBRANTIA. 177 



The largest Gallfly known in England is that which 

 produces the round hard gall now so common upon low, 

 or young oak-trees, and spoken of above as unknown 

 thirty or forty years ago. This insect (Cynips quercus 

 Lignicola, PL VI., fig. 3) was at one time believed to 

 be identical with that of the Aleppo Gall, the gall of 

 commerce, and to have been imported in the gall, after- 

 wards naturalizing itself in England. It is now, how- 

 ever, recognised as a distinct species, and the origin of 

 its introduction is as obscure as ever. For some time 

 attempts were made and renewed to utilize this Gall in 

 the manufacture of ink, but the tannin, or dyeing matter, 

 yielded by it is so inferior in quality to that of the 

 foreign species, that it seems unlikely that it should ever 

 supersede this. These Gallflies were, with those of an- 

 other species, made the subject of a curious experiment 

 by Mr. F. Smith ("ZooL" 7330). The male fly of the 

 Cynips being unknown, he collected about a bushel and 

 a half of the Galls, with the purpose of discovering it, 

 if possible. From all this number none but females 

 emerged. These he placed on oak-trees in various 

 places, and afterwards visiting them found new Galls 

 upon those trees, and on no others in the neighbourhood. 



From another species of Galls he obtained about 

 1200 Flies, all female, whilst Hartig, as Mr. Smith men- 

 tions in his paper, amongst 10,000 of one species and 

 4000 of another, could not discover a single male. 



The Gallflies are often rather heavier in figure than 

 most other of the Spiculiferous insects (see PL VI. fig. 3), 

 with which, however, they are very nearly allied, not only 

 in structure but even in habit, some species having been 

 discovered to share in the parasitic habits of those other 

 families laying their eggs in the bodies of other insects. 



