ARTHUR DEWITT WHEDON 403 



figure 6. In full grown larvae they extend from the middle of the 

 fifth to near the hind end of the eighth segment. In dorsal view 

 they adhere to the side of the tracheal trunks until close upon the 

 branchial basket, when they abruptly turn aside and ventrad a 

 short distance, then turn dorsad again and run parallel to the 

 trunks and for a half segment beyond their tips. The Vasa 

 Deferentia are small tubes of uniform diameter which continue 

 into the ninth segment, run beneath the anterior end of the Ad- 

 ductor Muscles of the Lateral Appendages, approach the median 

 line and turn a little forward to unite with the sides of the Sperm 

 Sac. The latter is of perfect cordate shape, and smaller than the 

 eighth ganglion. It lies in the triangular space between the 

 sternal muscles in the anterior part of the ninth segment. 



Female: — The Ovaries seem less developed than the testes in 

 larvae of the same size. They are flattened, cord-hke bodies 

 similar to those of Lestes Ijdng between and ventral to the dorsal 

 trunks, which they follow very closely from the first segment to 

 the fifth. In the region of the posterior lobe of the ventriculus 

 they narrow down to the size of the oviducts and run on back- 

 ward and downward about the alimentary canal. They pass 

 beneath the sternal muscles of segment seven about the middle, 

 converge and pass over the suture into segment eight, run beneath 

 the sides of the eighth ganglion, unite with each other for a short 

 distance and connect with the Sperm Receptacle or Bursa Copula- 

 trix. This is very small and undeveloped. No Accessory Sacs 

 were discovered. 



The Nervous System 

 (Plate XXIII, figures 8, 9, and 10) 



The nerve chain of A rax and Aeshna does not differ materially 

 from that of Lestes. The first ganglion lies against that of the 

 metathorax in the same way; the other seven, however, are placed 

 at the middle of each segment. The last one is as usual aT^out 

 twice the size of the others. The connectives are closely ap- 

 proximated forming a cord with nothing but a median line to 

 show its paired nature; the connectives between the last two 

 ganglia are separated by a space less than the width of one of the 

 connectives. There is also a slight separation of those between 

 the ganglia of the mesothorax and the metathorax. 



TRANS. AM. ENT. SOC, XLIV. 



