1912.] 2B1 



To finish with popular hypotheses, the Editor (J.c.) somewhat 

 tentatively " thinks " that if those who hear the noise would look 

 up quickly they would catch sight of a little cloud of " minute flies " ; 

 but this seems only a reiteration of Fred Barraclough of Barnsley, 

 who (at p. 120) had already tracked the humming to "a swarm of 

 small black insects or gnats with greyish wings a few inches above my 

 head, like may-flies hovering. On standing up they rose up in the 

 air and were very soon invisible." Here the matter ended at " small 

 black insects or gnats " hovering in the air, doubtless somewhat in 

 the manner of Culex detritus described by Haliday (Ent. Mag. 1833, 

 p. 151), and Douglas (Ent. Mo. Mag. 1895, p. 239) ; that the latter 

 was describing the gyrations of Cidex and not Chirononmis is olwious, 

 for he distinctly states that at rest the hind legs were elevated, 

 whereas in Chironomus it is the front legs which do not cling. 



Insects are the only creatures known to me that hum in the air, 

 consequently it was incumbent upon entomologists to discover an ex- 

 planation ; and this I have been seeking an opportunity of doing for 

 four years. The problem for long seemed insoluble. Often the peculiar 

 humming was heard, usually during the comparatively windless hush 

 before dusk, though this may be because other soimds are then less 

 apparent ; but never was there the least indication of swarming insects. 

 About 9 p.m. on 12th of last July (one of the hottest days this year), with 

 a maximum temperature of 85 and minimum of 61), the sound was very 

 prominent about the front lawn, but a diligent search failed of result. 

 The place is surrounded by trees, and the air at that time was practi- 

 cally still. Then I strolled round the house and found the tennis 

 court swept by a slightly gusty S.W. air of wind ; here the humming 

 was even more audible and, glancing up, I was rejoiced to see companies 

 of insects dancing in the air. As the gusts struck them they descended 

 and always rose to the height of invisibility during the frequent lulls, 

 the humming rising and falling in exact ratio to the insects proximity. 

 Here at last were the elusive hummers in visible form ; I netted a 

 couple of dozen of them and packed them off to Mr. F. W. Edwards, 

 who kindly tells me they are Chironomids of two species in equal 

 numbers, Tanyjms varins. Fab., and Chironomns dorsalis, Mg. ; adding 

 that the only reference to Chironomidae producing sound, known to 

 him, is in Williston's Manual of North American Diptera : " Over 

 meadows, in the Rocky Mountains, the writer has seen them rise 

 at nightfall in the most incredible numbers, producing noise like that 

 of a distant waterfall, and audible for a considerable distance." With 



