Observation relative to the Family Fidgoridse, 431 
Imperial University at St. Petersburg^ " On the Lumino- 
sity of Midges (Chironomidse) of wMcli an excellent 
translation has been published by our Dipterological 
associate, Mr. E. E. Austen. f 
The first observation on the luminosity of Midges 
{Chironomits) appears to have been made by Pallas, 
who ascribed the same to a species of gnat {Culex 
pipiens, L.)J. This observation slept till it was con- 
firmed in 1874 by W. D. Alenizyn, and published in a 
communication addressed to the ^'^Naturalists' Society 
of St. Petersburg.^' Subsequently Brischke, Ssorokin, 
and Tarnani reported the same phenomena, and this 
was again seen by Schmidt while staying at Lake 
Issykkul in 1892. 
This luminous species did not, as was at first imagined, 
prove to be undescribed, but was merely — according 
to Schiuer — a variety of Ghironomus plumosus, L., whilst 
certain smaller specimens appeared to belong to Ghi- 
ronomus tendens, Fb., thus demonstrating that, as these 
well-known species were not always, or to say the least, 
usually luminous, the luminosity observed must be of an 
occasional or aberrant character. 
Herr Schmidt proceeds in a deductive manner to seek 
the explanation of this luminosity; and he, firstly, 
separates two known causes, viz. : — 
A. Animals which are luminous by being provided 
with special luminous organs. 
B, Animals which are luminous by means of luminous 
micro-organisms living upon or in them. 
In the second category may be instanced the micro- 
organisms occurring as veritable parasites injurious to 
their host, such as the discovery by A. Giard of the 
luminosity of Talitrus, a genus of Crustacea, belonging 
to the order Amphipoda. On examining a foot belonging 
to one of these luminous crustaceans under the micro- 
scope, it was found swarming with micro-organisms 
* " Zoologische Jahrbiicher — Abtheilung fiir Systematik, Geo- 
graphie und Biologie der Thiere, Bd. viii., Heft. 1 (Jena, ^894), 
pp. 58-66. 
t " Ann. and Mag. Nat. Hist.," ser. 6, vol. xv., p. 133. 
J It is unnecessary to give, or rather to repeat, references which 
have been given by Schmidt, reproduced by Austen, and republished 
in the " Ann. and Mag. Nat. Hist."— W. L. D. 
