17 
for a moment to watch them, I saw a female fly to one of the oscillating 
males, which immediately followed her down. For a moment I did not 
comprehend what I had seen, but another female rose, and I noticed 
this time that one came in actual contact with the male, which also flew 
down after her, and, when I found them on the herbage, they were 
already paired. Before I left the field I had seen this repeated again 
and again, and had not the slightest doubt of the mearing of the 
peculiar motions of the male. This, subsequent observations have fully 
confirmed. The male humuli flies in this conspicuous manner that the 
female may see him, and his light colour very greatly assists this. Dr. 
Chapman, in recording what he had seen, expressed the opinion that 
it must have been noticed before, and, really, when you have once seen 
it, you cannot help thinking as he did, that it must have been observed 
long ago. The flight of the female at this time is, as he pointed out, 
very different from her flight when she is dropping her eggs over the 
herbage, and which, so far as I have seen, is always done later in the 
evening. There is another matter connected with the flight of humuli 
that has not, I believe, been recorded. That is, the fact that when 
several males are flying in close proximity, they amuse themselves by 
bumping together much as flies do around our curtain fringes. I had 
noticed this once or twice previously, but merely thought they were 
flying rather close together, and accidentally came in contact ; but last 
summer I convinced myself that it was no accident, but that they were 
really at play. I was on the railway side endeavouring to take Acidalia 
subsericeata , when I noticed two male humuli flying together. I stood 
and watched"them for some time, noticing that they occasionally came 
in actual contact, but not attaching any meaning to the act; presently, 
a third male appeared a few feet away. It quickly drew near the other 
two and then joined them, all flying close together, and two, or some¬ 
times all three bumping together and then swinging off again. Then a 
fourth came down from the top of the bank and joined in the game. 
They were so intent upon it they allowed me to stand so close that I 
could have touched them with my hand. At last I netted the four at 
a single stroke, and, immediately repenting I had disturbed them, I 
turned them out of the net. One flew away, but the other three actually 
returned to their play, and I left them there. Sometimes only two 
would collide, often three, but generally before they parted all four 
would be in close proximity if not in actual contact. They were rather 
clumsy, and it seemed as if they needed to swing backwards and for¬ 
wards once or twice before they could steady themselves sufficiently to 
direct their flight as they wished. Before I leave this species I would 
call attention to the fact that it is the only one of our “ Swifts ” in which 
the sexes differ in a very marked degree, 1 and, also, that the males 
occuring in the Shetland Islands, known as var. hethla?idica , are much 
more like the female than the ordinary form. So long ago as 1865, Dr. 
Knaggs called attention to the peculiar form humuli assumed in these 
Islands ( Ent . Ann ., 1865, p. 98), but little notice was taken of the 
matter, and it was not until Mr. Meek’s collector, some years later, 
brought a large number of these extraordinary specimens home, and 
they became generally distributed in our collections, that we began 
generally to understand what it was to which our attention had been 
1 I have always looked on H. sylvwus as presenting very marked sexual dimor¬ 
phism.—-J. W. Tutt. 
D 
