JUAN VINAS—THE WATERFALLS 195 



from recent rains. I climbed up as far as I could, until the 

 steepness was too great to furnish a foothold, but the insects 

 were still beyond the reach of my net handle. I descended 

 and hastily attempted to improvise an additional joint but 

 one stick after another broke, so I used my umbrella and 

 again climbed the bank. But the soft earth gave way and 

 collector, net and umbrella slid swiftly — and separately — 

 down to the tracks. A second attempt had the same result. 

 A third, made more cautiously, was so successful that the 

 net with its handle supported on the umbrella was thrown 

 over the accommodating pair, which had lingered for at 

 least ten minutes on the same branch, and by gently drag- 

 ging it down over the bank I at last got the insects safe in 

 my hands. Then I saw that this female was so like the fe- 

 males we had seen and taken pairing with inopinata males 

 that a minute comparison would be necessary to determine 

 whether there was any difference between them or not; yet 

 the males were very different. We saw no other pellucida 

 male pairing at any time during this visit to Juan Vinas, but 

 on October i, at the same fall, A. spied a pair of pellucida 

 mating, which we were able to secure. 



The detailed comparison of the single female taken pair- 

 ing with inopinata male and two females taken pairing with 

 pellucida males, with each other and with nine other females 

 taken singly, has failed to reveal any external features by 

 which they may be distinguished. 



On June 26 a few larvae were found at the farther waterfall 

 in among the roots that hung in front of the rock face and 

 were constantly bathed in the water. We suspected them 

 to be Thauviatoneura but not until ten months later did we 

 obtain the proof that they were so. These died very quickly 

 when placed in still water so that we were unable to rear 

 the adults from them. The next day we found one large 

 larva of the same kind but older, crawling up out of the water 



