40 



THE TRACHEATION OF WINGS 



10 ^ 



Fig. 30. — The basal connections of the tracheae 

 of the wings of Epeorus. Side view. 



union of the transverse basal trachea {th) and the cubito-anal trachea {cii-a) 



and connects with a small accessory trachea which leads anteriorly to the 



costo-radial trachea (c-r) . The remainder of the cubito-anal trachea which 



Morgan had suspected to be 

 present, was not found in any 

 of the specimens dissected. 

 Even this small vestige was 

 found to be absent in the 

 hind wing. 



The posterior stems of 

 the leg trachese {ps) are repre- 

 sented by slender tracheae 

 which enter the coxee in the 

 typical position for the pos- 

 terior stems of the leg tracheas 

 but their connections with the 

 anterior stems {as) are very 

 slight and seem to be lacking 



in some cases. It is very evident that the posterior tracheae to the legs 



are at the point of being lost in this form. 



There is a saucer shaped disc, which has been indicated by a dotted line 



in the figure, between the cubito-anal and costo-radial groups of tracheae 



in each wing. There is also a well developed apodeme, represented by a 



dotted line, just posterior to the union of the cubito-anal trachea {cu-a) 



and the transverse basal trachea {th) in each wing. The influence of these 



structures upon the tracheae of the wings will be taken up in the latter part 



of this paper. 



The basal connections of the wing trachece of Chirotonetes nymph, Order 



Ephemerida. — The conditions of the basal connections of the wing tracheae 



of Chirotonetes are more easily understood 



after having studied the conditions in 



Epeorus. In Chirotonetes (Fig. 31) the 



anterior tracheal connections to the legs 



and wings have retained their primitive 



condition but the posterior connections are 



entirely absent. Small muscle tracheae, 



somewhat resembling the typical posterior 



connections, were found but their former 



connections have been entirely lost and the Fig. 31.— The basal connections of 



1 r i-- r ^1 • 1 ^ i_i • the tracheae of the wings of 



cephahzation of the air supply to the wmgs Chirotonetes. Side view. 



is complete. 



The basal connections of the wing trachece of Apis nielli fica, Order Hymen- 



optera. — The pupa of a drone honey bee was used for the study of the trachea 



