184 PHILIP p. CALVERT. 



similar to the first opening described for Agrion, but the third joint bore four 

 tympanules; the profile of the tympanules was convex, and otoliths within very 

 evident. 



Packard has described as organs ot taste the setse and "'taste-cups" situated ou 

 the inner surface of the labrum (Psyche, V, p. 223, 1889). 



The sympathetic nerves of Libellula depressa have been described 

 and figured by Brandt (13). From either side of the brain, near 

 and in front of the origin of the antennal nerve, a nerve runs for- 

 wards and unites with its fellow of the opposite side in the fiontal 

 ganglion, from which a pair of small nerves is given off to the lab- 

 rum ; posteriorly the frontal ganglion gives off an unpaired nerve 

 to the oesophagus. Lying on the dorsal surface of the oesophagus, 

 immediately behind the brain are two pairs of small ganglia, of 

 which the anterior pair is on the middle line and in contact, while 

 the posterior pair is separated, each ganglion lying on the lateral 

 margin so to speak of the oesophagus ; anterior and posterior pairs 

 are connected ; nerves are supplied to the oesophageal walls. Ap- 

 parently it is the posterior pair which corresponds to the pair of 

 tracheal ganglia of Blanchard. 



We know but little as to the intelligence of the Odonata. Fennel records 

 (Mag. Nat. Hist. VI, pp. 271-272, 1833) an observation of interest on this topic. 

 A male and a female of a species of Aeschna were flying and sporting over a 

 pond, when another male appeared and chased the female. The first male 

 turned upon the newcomer, and a struggle ensued between the two males until 

 one fell into the water ; the other alighted upou him as he floated on the water's 

 surface, remained there for a short time and then joined the female, who had 

 continued to fly around the pond without manifesting any interest in the combat. 

 An examination showed that the conquered male had been deprived of his wings 

 by the victor, and so was unable to rise. A natural interest as to whether the 

 victor was the original possessoror the newcomer, is not gratified by the nariative. 



THE REPRODUCTIVE ORGANS. 



The Odonata are in all cases unisexual. The male reproductive 

 organs — testes are paired, one lying on either side of the abdomen 

 above the alimentary canal. Each testis is an elongated, cylindrical 

 organ, held in place by trachepe ; when fully developed, its anterior 

 extremity lies in the fourth segment. At its hind end each narrows 

 somewhat to form the vas deferens, which passes below the hind-gut 

 in the seventh or eighth segment and only unites with its fellow of 

 the opposite side at the common opening on the ventral surface of 9. 

 The two vasa deferentia are without permanent dilatations or seminal 

 vesicles. The opening of the common duct, as already mentioned, 

 is guarded by a chitinous flap on either side. 



