78 THE entomologist's record. 



drawn into that direction by the scent. I certainly did not see any 

 female fly past one of these oscillating specimens. A somewhat similar 

 habit has been recorded in the case of Hepialus humiili, where also the 

 female flew actually against the oscillating male ; and I feel no doubt 

 that this curious reversal of the usual order of things takes place in 

 each species in which the males, instead of flying in search of their 

 partners, oscillate over a limited space" {E.M.AI., vol, xxiii., p. no). 

 Since then I have frequently seen this species pair, and the female has 

 a curious manner on these occasions. Mr. Barrett describes it as 

 " buzzing about." I have spoken of it elsewhere as a " tumbling, 

 shuffling sort of flight." But this is only assumed when she comes 

 within the range of the diffused odour. Previously, and also when 

 dropping her ova among the bracken, she flies steadily enough. But 

 though the oscillating flight of the males is now explained in this 

 satisfactory way, there are some other points that are still puzzling. 

 When they are at all plentiful, the males may occasionally be found 

 on tree trunks, I never felt satisfied that this was selected as a place 

 of rest ; perhaps they merely climb up when emerging from the pupa, 

 though they are generally rather too high up for that. Besides, I have 

 occasionally found sylvinus on palings, and that is a species as given to 

 concealment as hectus. I have also been unable to satisfy myself as to 

 the meteorological or other causes which affect the flight of this insect. 

 One night, as Mr, Barrett mentions, they will fly in daylight ; I have 

 seen them with the evening sun shining on them as they flew, the 

 females appearing at the same time ; another night, they will swing 

 away for half-an-hour, and their sweethearts will never appear ; a third 

 night they will fly quite late ; and on a fourth they never put in an 

 appearance at all. Sometimes, when they fly, they seem to come out 

 all at once as though they came out at a signal. One night, I re- 

 member being in the wood ; there was not an msect to be seen, then 

 a single hedus appeared, and before I had boxed it, the place was alive 

 with them. I could net five or six at a single stroke, and got over fifty 

 in the twenty or twenty-five minutes they continued on the wing, about 

 a quarter of them being females. Then they disappeared as suddenly 

 as they had appeared, I was anxious to obtain specimens showing 

 silver marks on the hind wings, and went again the next evening at 

 the same hour. I could see no difference in anything. The weather 

 was as fine, the wind in the same quarter, but I never saw a specimen. 

 At other times they will come out at intervals for, perhaps, over an 

 hour, and not appear in large numbers at all, this is what might be 

 expected, but their sudden appearance in enormous numbers, and equally 

 sudden disappearance, or their absence on apparently suitable nights, are 

 not very easy to explain. A third item that has puzzled me is that 

 when sweeping the herbage, when I have often taken them in cop. I 

 have twice found a second female in the net, as though she had been 

 attracted to the male after he had paired with another. From one of 

 these females I obtained eggs that proved infertile. In these two 

 species the manner of flight is the same : the males swinging backward 

 and forward till they attract the females, the one by sight, and therefore 

 flying in an open and exposed place, and being light and shining ; the 

 other by scent, the diffusion of which is assisted by the motion, and 

 the insect, therefore, flying in a sheltered nook where the faint odour 



