194 ^ YEAR OF COST J RICAN NATURAL HISTORY 



The female made the usual abdominal movements seen in 

 the Zygopterous dragonflies generally, that is, those for in- 

 serting the eggs into plant substances by means of a sharp- 

 pointed ovipositor on the under side of her eighth and ninth 

 abdominal segments. Some of these movements, however, 

 were over hard wet rock so that it seemed unlikely that any 

 eggs were placed on it. At other times the movements were 

 made against moss and roots, the female occasionally bury- 

 ing her abdomen for half its length in the wet mass. We 

 had suspected such a habit even before we had seen the 

 living female, and had carefully examined some of the wet 

 moss, for larvae, but found none. The ovipositing female 

 is not accompanied or followed by the male. Indeed once a 

 female flew close to a resting male without attracting any 

 response from him. Males at least often remain on the 

 same spot half an hour or longer without moving. Females 

 seem less persistent, but one timed was ten minutes on the 

 same twig. Except in pairing males, the wings of both 

 sexes, when at rest, are held in the vertical position folded 

 together, but every now and then an individual will open 

 and close its wings once or several times in succession. 



Owing to the habit of Thaumatoneuras of spending most 

 of their time over these vertical wet rocks, their capture was 

 often only possible by climbing up on the rocks themselves, 

 or by hanging with one hand to some long dangling root or 

 vine and sweeping the net with the other. 



Up to July 30 the males which we observed in the pairings 

 of Thaumatoneura were in every case inopi?iata. On that 

 day P. saw a male pellucida and a female fly to a dead branch 

 on the side of the railroad cutting just west of the farther 

 waterfall and about twenty feet above the tracks. There 

 was no doubt that they were pairing, so it was highly de- 

 sirable to capture them both. The steep bank was com- 

 posed of reddish soil with loose stones and soft rock, wet 



