342 ENTOMOLOGICAL NEWS [Oct., *I4 



first time that this female was so hke the females which we had 

 seen and taken pairing with inopinata males that a minute com- 

 parison would be necessary to determine whether there was 

 any difference between them or not. We saw no other pairs of 

 pellucida until October i, 1909, when one was seen and obtain- 

 ed at the same waterfall. 



What we presumed to be egg-laying was watched in three 

 or four instances on June 24. The female made the usual ab- 

 dominal movements seen in the Zygoptera generally, that is 

 those adapted for inserting the eggs into plant substances. 

 Some of these movements were, however, over hard rock and 

 it seems unlikely that any eggs were placed on it. At other 

 times the movements were made against moss and roots. At 

 times the female had her abdomen buried to half its length in 

 the mass of wet moss. Pieces of roots and of moss in which 

 the oviposition had apparently been made were carried to our 

 room at Cartago and kept in water for months but we never 

 obtained any larvae from them. The ovipositing female is not 

 accompanied or followed by the male. Indeed once, on June 

 24, a female flew close to a resting male without attracting any 

 response from him. 



The Female. 



We have three females of Thaumatoneura taken while pair- 

 ing; one is that taken with inopinata male on June 27, 1909, 

 the other two taken with pellucida males on July 30 and Octo- 

 ber I respectively. Nine other females were taken singly. All 

 twelve females are compared in the accompanying table with 

 respect to all the differences which I have been able to detect 

 between the female of June 2'/ (No. 9) on the one hand, and 

 those of July 30 (No. 11) and of October i (No. 12) on the 

 other. It will be seen that these dift"erences are very slight and 

 that the positions of Nos. 9, 11 and 12 in the whole series are 

 such as to render it unlikely that females of inopinata can be 

 distinguished from those of pellucida by any of these features. 



Male Dimorphism. 

 This apparent lack of external characters separating the fe- 

 males pairing with pellucida males from that pairing with in- 



