8082 



Insects. 



species, namely, Mesoleptus limitaris, Grav., Tryphon cephalotes, 

 Grav., T. raelanoleucus, Grav., T. bipunctatus, Grav. Probably all 

 the parasites mentioned by Ratzeburg as having appeared from 

 Nematus Ribesii, Scop. (?), will be found to harbour in this species. 

 It is impossible to state with certainty whether Reaumur, in his 



* Me moires,' vol. v. pp. 94 and 125, pi. 10, figs. 4 — 11, had this or 

 another species in view. Had not Dahlbom stated in his ? Synopsis,' 

 quoted at the head of this paper, that his Grossularia larvae fed on the 

 leaves of the gooseberry as well as on those of the currant, I should 

 have supposed that this otherwise so accurate naturalist had confused 

 two species together, the more so that T am acquainted with two 

 species of Nematus which have many points of agreement with this 

 N. ventricosus. But Reaumur, in the body of the work, gives his 

 larva twenty-two legs, and in the description of the plates only 

 twenty : this appears to warrant us in supposing that in this matter 

 Reaumur has not gone to work with his usual exactness, which would 

 tend to do away with the interest we might have in determining 

 whether his species was the same as ours. 



Leon Dufour has treated of this subject in a paper entitled ' Etudes 

 pour servir a l'Histoire du Nematus Ribis,' published in the 6 Annales 

 de la Soc. Ent. de France,' 2me serie, torn. v. p. 571 (1847). 

 According to this writer, Dahlbom has made the mistake of stating 

 that the Nematus of Reaumur is identical with his N. Grossulariae, 

 and was quite inaccurate when he maintained that the writer of the 



* Memoires' had made an error in describing the number of legs. 



Although we have no wish to enter into the vexed question about 

 synonymy, which would lead to no result, we cannot help expressing 

 our disapproval of the way in which Leon Dufour has treated the sub- 

 ject, calling his species Ribis, although he himself states that it is not 

 the Tenthredo Ribis of Schrank. This employment of the same 

 specific name can only give rise to confusion. Again, Leon Dufour 

 states, " D'abord la larve du Grossulariae a vingt pattes, et je ne 

 conteste pas a M. Dahlbom son exactitude numerique ; celle du 

 Ribis n'en a que dix-huit," whilst, from what is said at p. 574, it ap- 

 pears that his larva had besides the eighteen legs, " une saillie infe- 

 rieure du dernier segment de l'abdomen, saillie ou se trouve l'anus, et 

 sert, par son epanouissement bilobe, a s'appuyer sur le plan de sup- 

 port, soit pour favoriser la locomotion, soit pour maintenir la larve 

 dans les attitudes souvent grotesques qu'elle prend sur les bordes des 

 feuilles." Now, seeing that every one except Dahlbom counts this 

 "epanouissement bilobe" for a pair of legs, Dufour should have 



