Luminosity of Midges. 135 



For ray own part, I had the good fortune to be myself a 

 witness of this interesting manifestation while staying at 

 Lake Issykkul in the summer of 1892. Unfortunately I 

 arrived at the lake too late to be able to witness the pheno- 

 menon in the height of its brilliancy ; for, according to the 

 statements of the inhabitants of Prshewalsk, the luminous 

 midges are most abundant at the beginning and in the middle 

 of June, while I did not reach the spot until the commence- 

 ment of July. This is my explanation of the fact that it was 

 only with a considerable amount of trouble that I discovered 

 and obtained six specimens of the luminous insects in the 

 shrubs growing on the shore of the lake, for otherwise, 

 according to the descriptions of the inhabitants, they frequently 

 appear in such multitudes that entire shrubs appear as if 

 aglow. 



The specimens observed by nie, of which one proved to be 

 a male and the remaining five females, shone very brightly, 

 with a somewhat greenish phosphorescent light, which was 

 entirely similar to that of Lampyris, but materially differed 

 therefrom owing to its continuity and regularity. 



Even when touched or actually thrown into alcohol the 

 insects still continue to shine, and apparently are able neither 

 to diminish their light nor to cause it to cease. In alcohol 

 the midges remain luminous for from three to four hours, as 

 was also previously found to be the case by Alenizyn. 



Unfortunately the only preservative fluid which I had with 

 me was 70° alcohol, and I was consequently obliged to be 

 content with bringing the specimens which I had collected 

 to St. Petersbui-g in the spirit. 



Since the phenomenon that I had observed interested me 

 in the highest degree, I proceeded in St. Petersburg to make 

 a closer examination of my specimens, and also consulted the 

 material brought back by Ssorokin and Alenizyn *. 



As a matter of fact, the collection forwarded by Ssorokin 

 proved to be in a perfectly useless condition : the antenna;, 

 legs, and in part also the wings of the majority of the speci- 

 mens were broken off, and their colour and markings appeared 

 to be greatly altered, so that it was not worth while to attempt 

 either a determination or description of the insects, or even 

 an investigation of them by means of sections. 



On the other hand, the collection, although such a small 



* The former was kiadly handed over to me by Herr J. N. Wagner, 

 Keeper in tlie Zoological Museum of the University of St. Petersburg, 

 the latter by llerr J. A. Portsehinsky from the collections of our Ento- 

 mological [Society. I venture to take this opportunity of expressing to 

 both of these gentlemen my warmest thanks. 



10* 



