An Odonate Nymph from a Thermal Spring. 



63 



ARTICLE V— AN ODONATE NYMPH FROM A 

 THERMAL SPRING. 



By D. S. KEivUCOTT, Columbus, O. 



I received recently, for study, from Dr. Josua Lindahl, four 

 diagon-fly nymphs, obtained by him from Mr. Lloyd T. Steven- 

 son, of Chat, Cal., with the following data (condensed) : 

 " Taken August 3d from a hot spring forty three miles west 

 of Reno, Nev., in Lassen County, Cal. The elevation of the 

 spring is about 4,600 feet ; it forms a pool forty-five feet long, 

 ten wide, and an average of three deep, and has no outlet. 

 At the western end, where the water issued from the rocks, 

 the temperature was near the boiling point ; at the opposite 

 end it was as low as bloodheat. No vegetation was noticed 

 in the hotter part, but in the cooler, certain plants were grow- 

 ing. The water is quite heavily charged with minerals. 



" The smaller nymphs were taken in the hottest part of the 

 pool, and the larger one in the cooler part. Ten or twelve 

 nymphs were seen. The smaller ones soon died, as the water 

 in which they were placed when collected cooled." 



The presence of animal life in mineral springs of high tem- 

 perature is a subject of deep interest to biologists, as the abil- 

 ity to withstand such conditions raises many interesting ques- 

 tions. While the references, at hand, regarding plants, mostly 

 algae, in hot springs are numerous and definite, those made on 

 animals in like situations are few, and among these I have 

 found no allusion to adolescent dragon-flies in such waters.* 

 But the presence of these strictly carnivorous nymphs is of 

 itself evidence that other animals were present, as it would 

 not seem possible for these young to feed on their own kind 

 from start to finish. 



Of these larvae at hand for description one is nearly mature, 

 while three are much smaller, having apparently passed about 



* It is regretted that the exact temperature was not ascertained at the time and 

 place of capture of these nymphs .Steps will doubtless yet be taken to secure this 

 important fact for different parts of the pool. 



(Jour. Cin. Soc. Nat. Hist., Vol. XIX, No. 2.) I Printed March 24, 1807. 



