Luminosity of Mldyes. 139 



spider (the lieacl was bitten off), and nevertheless its body 

 was luminous, although not so brightly as in the case of the 

 living insects. 



3. The luminous insects are very sluggish, whereby they 

 differ considerably from our own midges belonging to the 

 same species. In his communication on the subject of the 

 luminous insects observed on the Sea of Aral, Alenizyn writes 

 as follows * : — " I have observed no independent movements 

 on the part of the insects ; those that I took in my hands 

 remained perfectly motionless. On being touched a few 

 individuals appeared to make indistinct movements, but they 

 usually fell down when this was done, and, since they 

 collected for the most part on the outside of the ship's 

 bulwarks, they thus dropped into the water." Almost the 

 same statement is also made by Ssorokin as to the luminous 

 Chironomidse on Lake Issykkul f, and from my own expe- 

 rience I can but confirm his words. According to the state- 

 ments of the inhabitants the luminous insects are very rarely 

 seen in flight, but always sit almost motionless on the 

 branches of the bushes, a fact of which I was likewise able 

 to convince myself. It is sufficient to hold a small box, a 

 glass, or simply one's open hand beneath the luminous insect, 

 and to shake the branch slightly, whereupon the midge falls 

 down into the box or into the hand, and does not even 

 attempt to fly away. Altogether the luminous insect conveys 

 the impression of a sickly and, at any rate, an abnormal 

 individual. 



4. Neither by Kusnezoff J, who examined the collection 

 forwarded by Ssorokin, nor by myself by means of making 

 sections (borax-carmine and paraffin) were any structures 

 whatever discovered resembling luminous organs. The fairly 

 well-preserved midges whicli were obtained by Alenizyn (my 

 own are in a much worse state of preservation, since I had 

 carried them in tnbes with ordinary corks, in consequence of 

 which the spirit probably evaporated to a certain extent) 

 exhibit in the sections only a strongly developed fat-body 

 with its typical widely areolate cells. 



5. The males are luminous as much as the females, and, 

 consequently, the luminosity can scarcely be of service from 

 a sexual point of view ; it is self-evident that the luminosity 

 cannot either serve as a lure, since the midges are not preda- 

 ceous insects. 



The analogy between the first three points and the above- 

 quoted observations of Giard is so obvious that it scarcely 



* Loc. cit. vol. xii. f I. D- Kusnezoff, loc. cit. p. 170. 



X Loc. cit. p. 170. 



