38 



THE TRACHEATION OF WINGS 



and extends parallel to the dorsal longitudinal trachea {d.li). Its only 

 connection with the wing trachea is at its point of origin. 



Fig. 27. — The basal connections of the tracheae of the wings of Ryacophila. 



vSide view. 



The basal connections of the wing trachecB of an unknown genus (Limno- 

 philidcB), Order Trichoptera. — This form illustrates an interesting step in 

 the reduction of the tracheae to the wings. (Fig. 28) . In the hind wing both 



Fig. 28. — The basal connections of the tracheae of the wings 

 of unknown genus of Trichoptera. Side view. 



the costo-radial (c-r) and cubito-anal tracheae (cu-a) are present altho the 

 latter is very small as is also the transverse-basal trachea {tb). In the 

 front wing the cubito-anal trachea and the transverse basal trachea are 



