32 CLASSIFICATION. 



of parasites and inquilines. The latter, it may be 

 added, are much more easily bred than the gall-flies 

 themselves. 



Classification. 



The origin of the name " Cynips " has been already 

 discussed (vol. iii, p. 140). Westwood was the first 

 who separated generically any of the species from 

 Cynips by forming the genus Biorhiza. Hartig added 

 ten more, namely, Andricus, Neuroterus, Teras, Rhodites, 

 Diastrophus, Spathog aster, Trigonaspis, Aulax, Ce- 

 roptres, and Synergies, the last two being inquiline 

 species, as he was the first to discover. Hartig' s 

 primary generic character was the length of the radial 

 cellule and the position of the areolet ; next followed 

 the form and number of the joints of the antennae ; 

 while for subsidiary characters he took the form of 

 the scutellum, the texture of the thorax, and the num- 

 ber of joints in the maxillary and labial palpi. In 

 1859 (Verh. z.-b. Gres. Wien) Giraud erected the 

 genus Dryocosmus, and ten years later Foerster formed 

 some more genera, and brought the whole to a focus 

 according to the lights of his time. His synoptical 

 table is here reproduced : 



1 (42) Wingless or winged ; in the latter the areolet lies quite close 



to the base of the radial cellule. 



2 (5) Wingless. 



3 (4) Antennae 14 — 15-jointed. Biorhiza, West. 



4 (3) Antenna? 13-jointed. Apophyllus, Htg. 



5 (2) Winged. 



6 (13) Radial cellule closed on the fore margin. 



7 (10) Scutellum with an impression. 



8 (9) The first abscissa of the radius angular, broken. 



Pediaspis, Tisch. 



9 (8) The first abscissa of the radius only slightly elbowed. 



Bathyaspis, Foerst. 



10 (7) Scutellum without an impression. 



11 (12) Radial cellule short and broad. Bhodites, Htg. 



12 (11) — — elongate. Hololexis, Htg. 



13 (6) — — open at fore margin. 



14 (15) Mesonotum without parapsidal furrows. Ameristris, Foer. 



15 (14) — with parapsidal furrows. 



16 (21) Foveas at the base of scutellum united. 



