146 FAMILY OTNIPID^. 



Figites) the mesopleura is separated from the sternum 

 by a keel. The scutellum is large, and varies con- 

 siderably in form. With a few exceptions it has one, 

 or more often two, fovege at the base. In Allotria 

 it is but little prominent; in other genera (Cynips, 

 many Figitina, &c.) it is raised, ovate, or orbicular; 

 in the Eucoelides it is large, and bears on the top a 

 more or less deep cup-like depression, and in this 

 group, further, its edge is distinctly margined, and 

 frequently projects more or less sharply ; in Onychia it 

 is channelled ; in Aspicera, ^gilips, and some other 

 genera, the top or apex is produced into a sharp or 

 blunt spine or projection. In sculpture it may be 

 alutaceous, punctured, rugose, or perfectly smooth ; it 

 may be shining or opaque. 



The metathorax (and the median segment) is usually 

 overhung by the large projecting scutellum. The 

 metanotum is of very small dimensions, being almost 

 hid between the scutellum and the median seg- 

 ments. The metanotal, pleural and sternal regions are, 

 however, perfectly distinct, as is also the metanotal 

 stigma. 



The median segment, unlike what we found in the 

 Tenthredinidae, is distinctly separated by the petiole 

 from the abdomen, and forms more than it does in the 

 last-named family an integral part of the thorax. It 

 is well developed posteriorly, and frequently bears 

 longitudinal keels, or may have more or less clearly 

 defined areas, or may be reticulated. The stigma of 

 the median segment is large. As in the Tenthredinidse, 

 the ventral portion of the median segment is aborted. 



It may be noted that English writers, when describ- 

 ing the aculeate or parasitic section of the Hymenoptera, 

 call all that part of the thorax behind the scutellum 

 the " metathorax ;" whereas there are really two seg- 

 ments, namely, the metathorax, or third segment 

 (= the post-scutellum auct.), and Latreille's median 

 segment, or fourth thoracic segment; that is to say, 

 the thorax is composed of four distinct segments. 



