134 HeiT Peter Schmidt on the 



mentioned Diptevon, while, on the other, ahnost all the species 

 of Chironomus are extremely similar to the true g-nats 

 (Culicidse) in outward appearance, and in a superficial deter- 

 mination may easily be mistaken for them. 



For a very long- time the observation iu question remained 

 altogether unnoticed and unconfirmed. It was not until the 

 year 1874 that the interesting fact was discovered for the 

 second time by W. D. Alenizyn, a member of the well-known 

 Aralo-Caspian Expedition, by whom it was published in a 

 communication addressed to our Naturalists' Society of St. 

 Petersburg*. 



During his sojourn on the Sea of Aral, and in the neigh- 

 bourhood of the mouth of the Amu Daria, Alenizyn was able 

 to observe that a multitude of actively luminous midges 

 settled on board ship. He also had an opportunity of 

 collecting these insects in alcohol, and of subsequently deter- 

 mining them to be a species of Chironomus. 



The next statement on the subject of the phenomenon 

 which we are discussing is to be found in foreign literature. 

 In the year 1871 two luminous female specimens of Chiro- 

 nomus were observed by Dr. Brischke on the River Kadauiie, 

 in Pomerania, and were determined by him to belong to 

 Chironomus tendens, F.f 



In the year 1884 luminous midges were observed on Lake 

 Issykkul by Prof. Ssorokin, the botanist, by whom specimens 

 were collected and forwarded in alcohol to St. Petersburg. 

 On arrival they were examined by I. D. KusnezofF, but, in 

 consequence of the bad state of their preservation, it was 

 impossible to determine them precisely |. 



In addition to these statements from literature, I am able 

 to adduce a verbal communication from Herr I. K. Tarnani, 

 according to which luminous midges, probably also belonging 

 to the Chironomidge, w^ere likewise observed near Taganrog, 

 on the Sea of Azov. The specimens of the insects which 

 were collected by Tarnani have unfortunately been lost. 



During the pa;t year (1893) our Entomological Society 

 received a luminous Chironomus in a dry condition, forwarded 

 by Herr Christoph from Sarepta (Saratow). 



The foregoing paragraphs are sufficient to show that the 

 luminosity of midges is a phenomenon which is of somewhat 

 widespread occurrence, although seldom observed by 

 specialists. 



* 1b the Society's * Trudy,' vol. vi. 1875, p. xi. 



t " Leuchtende Dipteien," Deutsche eut. Zeit. Jahry. xx. 1876, Heft 3. 

 Entom. Monatsblatter v. I). Kraatz, Berlin. 

 X I. D. Kusnezoff, loc. cit. p. 170. 



