32 



THE TRACHEATION OF WINGS 



The basal connections of the wing trache<s in a nymph of Pteronarcys, 

 Order Plecoptera. — The conditions of the wing and leg tracheae in the stone- 

 flies (Fig. 19) is somewhat compHcated by the presence of tracheal gills 



r.sf>i 



Fig. 19. — The basal connections of the wing tracheae of Pteronarcys. Dorsal view. 



but the relationships are quite generalized. The typical Y-shaped leg 

 tracheee are present in both cases, but in the case of both legs the posterior 

 stem (ps) is connected with a trunk leading from the spiracle to the tracheal 

 gill (gt) . The cubito-anal wing tracheee (cu-a) have diverged from the leg 

 trachege until they have attained independent origins. 



The conditions of the anterior branches to the legs and wings have not 

 been modified and the wing trachea (c-r) arises in common with the anterior 

 stem of the leg trachea (as). 



The dorsal longitudinal trachea (d. It) is well developed but it will be 

 noticed that it has no direct relationship to the wing tracheae. 



The basal connections 

 of the wing trachecu of 

 Chauliodes, Order Neur- 

 optera. — The wing tra- 

 cheae of Chauliodes (Fig. 

 20) represent no great 

 deviation from the 

 typical condition. It 

 is interesting to note 

 that the cubito-anal 

 trachea (cu-a) and the 

 posterior stem of the leg 

 trachea (^5) are separated at their bases in both cases and that the costo- 

 radial tracheae (c-r) and the anterior stems to the legs (as) are connected 



Fig. 20. — The basal connections of the wing tracheas 

 of Chauliodes. Dorsal view. 



