Field Notes, 269 



appear to have been identified. None of the above are in the 

 list of Yorkshire diptera in the Victoria County History, nor 

 does Wingate include them in his hst of Durham diptera ; the 

 last two are given in Cooke's list of Cheshire and South Lanes, 

 diptera in The Naturalist, 1880. I have spare specimens of 

 C. pallida if any one would care to have them. — Chris. A. 

 Cheetham, Farnley, Leeds. 



— : o : — 

 The Pairing of the Genus Hepialus. — The interesting 

 observation of Mr. Morley on p. 234 of the current volume of 

 The Naturalist and Mr. Porritt's comment thereon, lead me to 

 hope that my views on the subject of Hepialid pairing may be 

 of interest, if not of much value. I have always been interested 

 in the alleged unmaidenly conduct of the females of H. humuli 

 and H. hectus. Collecting recently in a wood where the latter 

 species is unusually common (and unusually variable), I have 

 tried to get an accurate view of what takes place when the 

 insect is making love. I have seen the complete series of 

 events twice only, but on each occasion affairs were conducted 

 in the same way. We start with a row of hectus ^ along the 

 edge of the path, flying over the bracken in their characteristic 

 way. Each one flies in an irregular, curved orbit of very small 

 extent and the orbits of two insects rarely cross. If undis- 

 turbed a male hectus will fly for a long time without moving a 

 yard from the spot where he first settled into his evening flight. 

 After a time the female appears. She is not very visible in the 

 growing dusk and I am not at all certain where she comes from. 

 My impression, however, is that she rises from the bracken under 

 the male. In neither of the cases observed did she appear to 

 arrive from the outside world, nor did she when over sighted 

 pay any attention to any male but the nearest. When once on 

 the scene, she flies in an orbit like that of the male, her orbit 

 mingling with his. The male flight becomes at once more 

 jerky and agitated. They fly together thus for several minutes, 

 jostling each other once or twice, though this appears to be due 

 to the nature of their flight and not to the intention of either 

 of them. A few minutes after the female's first appearance 

 she settles rather abruptly on the under side of a bracken 

 frond. The male almost instantly flies to her. Copulation 

 takes place at once and the male hangs head downwards, his 

 entire weight supported by the combined genital organs. 

 While all this is going on there are several other males flying 

 within a few feet, who take not the least notice of the pro- 

 ceedings. It seems to me that the female does not so much 

 seek the male as accost the first one she comes across. Where 

 the species is common he does not require much seeking. Al- 

 though the males are apparently in great numerical superiority, 

 she seems to have no attraction except for the one to whom she 



918 Aug. 1. 



