34 



THE TRACHEATION OF WINGS 



The basal connections of the wing trachece of a notonectid nymph, Order 

 Hemiptera. — The costo-radial tracheae (Fig. 22 c-r) arise from the anterior 



Fig. 22. — The basal connections of the wing tracheae of a 

 notonectid nymph. Side view. 



stem of the leg tracheae {as) . The bases of the cubito-anal tracheae {cu-a) 

 have diverged from the posterior stems of the leg tracheae (ps.) and have 

 come to arise in common with muscle tracheae {mt) which pass to the median 



part of the body. The condi- 

 tions of the wing tracheae are, 

 however, so near the typical that 

 there is no difficulty in vmder- 

 standing the relationships. 



The leg tracheae are modified 

 to a greater extent. In the 

 meso-thorax the anterior and 

 posterior stems to the leg (as 

 and ps) unite to form the typical 

 Y-shaped leg trachea and at 

 their point of union give off a 

 large muscle trachea (nit.). The 

 posterior stem of the leg trachea 

 in the metathorax (ps,) lies 

 laterad of the anterior stem (as) 

 at their point of union and the 

 muscle trachea (mt) appears to be a continuation of the posterior stem 

 of the leg trachea (ps). 



Fig. 23. — The basal connections of the wing 

 tracheae of a corisid nymph. Side view. 



