670 Chronicles of Science. [Oct., 



Walsh's hypothesis rests entirely on the identity of the galls,* 

 and that the characters he gives of Cynips spongifica produced from 

 the summer gall, and of Cynips aciculata from the winter gall, 

 require, from morphological considerations, that they should be 

 generically separated. The transition forms which Mr. Walsh finds 

 between the two galls signify nothing. Galls of various species 

 of cynips often appear to be transitional between other forms, and 

 are only known with certainty when the insect appears. Thus Rein- 

 hard says that the galls of C. lignicola are scarcely to be distin- 

 guished from those of C. conglomerata, or the latter from those of 

 C. Kollari, although all three galls when fully and normally formed 

 appear very different. So with the galls formed on oak-leaves by our 

 European species, as those of G. folii, G. scutellaris, G. longiventris, 

 G. agama, G. divisa, and G. disticha, which resemble each other so 

 much, that it is not to be wondered at if some examples appear to 

 form a transition from one species to another. In further confirma- 

 tion of the deceptive resemblances between galls of widely different 

 species, compare those of Lasioptera rubi with those of Diastrophus 

 rubi, or*of Cecidomyia circinans^ with those of Neuroterus lanuginosus. 

 Mr. Walsh appears to have erred in the belief that it is only males 

 which are hatched from unfertilized eggs, for, according to Dr. von 

 Siebold, in the Psychidce, the unfertilized eggs give only females. 



Still the facts brought forward by Walsh to bear on his hypothesis 

 are so remarkable, that it is necessary to seek other explanations. 

 Reinhard suggests that G. spongifica may either be an inquiline of 

 C. aciculata, or that G. spongifica and G. aciculata may be generically 

 distinct species, only making similar galls. If C. spongifica be an 

 inquiline, then it will form an exception to the rule that inquilines 

 always appear either at the same time or after the gall-maker ; further, 

 C. spongifica had an inquiline of its own (Synophrus laiviventris, Ost. 

 Sack.), while with G. aciculata nothing else appeared. 



So far as negative evidence can go, the male sex of many genera of 

 Cynipidas has no existence, so that reproduction is exclusively confined 

 to the females. Unwilling to adopt this conclusion, it has been at- 

 tempted to show that the males may be among the inquilines. Reinhard, 

 however, objects to this : he thinks that if there were really dimorphism 

 in the females, so that both the inquiline female and the maker of the 

 gall were served by the male inquiline of the former, that only the 

 same species of inquiline would be found in the same gall. This is 

 by no means the case, as Hartig has bred from Cynips folii, Synergus 

 nigripes, S. flavicomis, &c, and from Biorhiza renum, Synergus tibialis, 

 S. luteus, &c. Furthermore, inquilines ought only to occur in the 

 agamic genera, whereas, on the contrary, they are found in the galls 

 of such bisexual groups as Andricus, Teras, and others. All the 

 genera appearing in summer are two-sexed, the flies taking a short 



* Mr. Wilson Armistead, of Virginia House, Leeds, who " has been an observer 

 of galls and similar excrescences for twenty years or more," is " preparing a volume 

 to contain the result of these observations." He makes an earnest appeal to all 

 naturalists for information and any particulars respecting them. 



t Lasioptera and Cecidomyia belong to the Diptera. 



