WING-VENATION OF THE PLECTOPTERA. 
159 
There is a separate costal trachea C, lying far above So ; the latter trachea 
lies far above the group of R and M, which arise close together well down 
towards the cubito-anal group. Rs arises from R very close to the point 
Text-pig. 9. 
Amektus ornatus (Eaton). Traclieation of hind-wing in («-|-S)th or penultimate 
larval instar. For lettering, see p. 162. ( x 87.) 
where M curves slightly upwards, so as to come very close to it. Rs divides 
into two branches, R2+3 and R4+6, each of which gives rise to a simple triad 
with incomplete traclieation. The middle branch of the triad of R9+3 is 
supplied by the trachea R3, but Rj and the distal part of R3 have no trachese. 
The two outer branches of the triad of R^+s have their tracheae present^ but 
Text-fig. 10. 
Ameletvs urnatics (Eaton). Venation of hind- wing 
For lettering, see p. 162. ( x 16.) 
the middle branch has none. M gives rise to a simple triad in which the 
trachea supplying Mg^.^ switches up into the middle branch distally, leaving, 
the distal half of M^ without a trachea. Cu2 has no trachea. 
LINN. JOURN. ZOOLOGTj VOL. XXXV. 11 
