136 Hen- Peter Schmidt on the 



one, brought back by myself, and the fairly large series 

 obtained by Alenizyn, afforded several specimens which 

 were perfectly well preserved. 



On commencing the investigation I was thoroughly con- 

 vinced that the luminous species of Chironomus with which I 

 had to deal were new, and I consequently intended, with the 

 help of the tables contained in Schiner's classical work 

 * Fauna Austriaca : Diptera,' to determine their systematic 

 position only approximately. My astonishment may there- 

 fore be imagined on finding in these tables a diagnosis which 

 corresponded with the majority of the specimens down to the 

 smallest details. 



For it appeared that both all tlie midges brought back by 

 myself from Lake Issykkul, as well as the majority of those 

 collected by Alenizyn, belong to Chironoimis intermedius, St., 

 a species which, in the opinion of Schiner, is merely a variety 

 of the extremely common Chironomus plumosus, L., since the 

 two forms are distinguished one from another only by size, 

 and also in this respect transitional forms are found between 

 them *, 



It IS therefore possible that also certain females examined 

 by me. which exceed the stated dimensions of Ch. mtermedius, 

 St., are to be regarded as belonging to Ch. jylumosus, L. 



1 have determined certain smaller specimens among 

 Alenizyn's insects as Chironomus tendens, Fb., but am not 

 altogether convinced of the accuracy of this determination. 



Besides the above, the same collection contained several 

 specimens of quite small midges, which proved to belong to 

 a species of Corethra, and yet are stated by Alenizyn j to be 

 actively luminous — a fact which is quite new to science. 



Unfortunately I was not in a position to confirm my 

 determination by a comparison of the specimens examined 

 by me with any determined by a competent dipterologist. 



Nevertheless I find a confirmation, although an indirect 

 one, of my opinion that the insects which I collected myself 

 at Lake Issykkul are really nothing else than Chironomus 

 intermtdius^ St., in the fact that on dredging in the lake \ 

 1 found a few specimens of the extremely characteristic larva 

 of Chironomus plumosus, L. The larva?, which were like- 

 wise preserved in alcohol, proved on closer investigation to 

 be absolutely identical with Reaumur's description and 



* Vide Schiner, op. cit. Bd, ii. p. 601. 



+ Accoi'diug to a communication from lierr J. A. rortscliinsk}-. 



X In Ka,ra-ssu Bav, near Prshewalsk, 



