ON STRUCTURE 137 



thereby enclosing two cells, the upper basal cell (B) 

 and the lower basal cell (C). From the centre 

 of the apical nerve of each of these cells extends 

 a longitudinal nervure ; the upper of these runs 

 out nearly to the apical margin of the wing and is 

 called ; the cubital nervure ( 6) ; this is united to the 

 nervure of the marginal cell by one, two, or three 

 cross nervures, enclosing thereby one, two, or three 

 cells called the first (D), second (E), and third (F) 

 submarginal cells. The nervure from the lower 

 basal cell is a short one, as it is met by a cross 

 nervure called the first recurrent nervure (10), which 

 runs from the cubital to the posterior ,th.Qieby enclos- 

 ing two cells, the first (G) and second (H) discoidal. 

 The second recurrent (11) leaves the cubital nearer 

 the apex of the wing than the first, meeting a 

 nervure which, springing from the outer posterior 

 angle of the second discoidal, closes the third 

 discoidal (7), and, curving slightly upwards, 

 nearly reaches the apical margin of the wing. 

 Beyond the second recurrent, and behind this 

 last nervure which we have been talking about, 

 are two spaces not actually enclosed, but called 

 the first (J) and second (K) apical cells. 



The posterior wings have very few cells. 



