144 FAMILY CYNiPIDjE. 



further terminate before reaching the costa, thus 

 leaving the radial cellule open at the base. On the 

 other hand, if it runs along the costa to the end of 

 the radial cellule (thus giving the costa there a thick- 

 ened appearance), the latter is called closed (PI. IV, 

 fig. 21). This completeness or incompleteness of the 

 subcostal nervure is of much value in classifying and 

 separating the species. 



Next in importance to the subcostal nervure is the 

 radial nervure (d). It issues from the subcostal, 

 usually at the point where the latter bends upwards to 

 join the costa. It may be either straight, running 

 almost parallel with the costa, or may curve downwards, 

 then curving up again to join the costa. In Cynips, &c., 

 it becomes angled immediately after leaving the sub- 

 costal, and may then proceed backwards to unite with 

 the cubital nervure (PI. IV, fig. 20 c). In this case it 

 has the appearance of issuing from the cubital nervure, 

 from which it proceeds in a straight line to the end ; 

 and of being united to the subcostal by a short-angled 

 nervure (b). The cubital nervure (e) issues from the 

 transverse basal nervure (#), which is always present. 

 It leaves the basal nervure above the middle, as in 

 Ibalia ; exactly at the middle, as in Cynips ; below the 

 middle, as in the Figitina ; or almost from the middle, 

 as in Allotrina. The cubital nervure is not always 

 complete or distinct; it may be entirely obliterated 

 before or behind the areolet, and is usually so faintly 

 indicated as to come into fche category of " venae 

 spuriae." The median nervure (/) is seldom prolonged 

 much beyond the basal nervure, and may be obliterated 

 or very faint. 



The radial cellule (3) is always present. In shape 

 it is narrow and elongated, not angled in the middle, 

 as in Cynips, Dryophanta, and other gall-makers ; or 

 short, broad, and angled or curved in the middle, as in 

 the parasitic species. 



In the former case the second cubital cellule (areola 

 or areolet) (6) is at its base (PI. IV, fig. 21); in 



