Kirx.—Mating-habits and Early Life-history of Opifex fuscus. 401 
While it is in progress the two insects rest quietly, in the end-to-end 
position, on the water or on a rock. Copula usually lasts from three to 
seven sae but it has been observed to last over half an hour. 
is by no means an uncommon thing for a male pupa to be captured, 
and in “this case the captor does not discover his mistake es emergence 
is about complete. He then darts away, one can fancy, with a expression 
of disgust, and after a little time resumes his place among the hunting 
males 
When warming is active it never happens that a captor is allowed 
оар possession of the captive. Three or four ог a dozen other males 
will have leapt at the same time, and a fierce struggle takes place, the 
successful captor making for the shore, stabbing with his proboscis and 
dragging the struggling mass along. The competitors seem to use their 
ungues in thrusting or dragging each other away, and the proboscis is 
apparently used freely. But the struggle never lasts long. Apparently 
it is abandoned as soon as it is recognized that the captor has a sufficient 
hold with the forceps to prevent loss of the captive. I have never seen a 
but probably if the rivalry were never successful it would not exis 
occasionally sees two males wit n the same pupa, сизелде їп 
opposite directions. In these cases the one that drags the pupa head 
forward is successful. 
rom a long series of оарои it seems evident that the method 
of the copula is usually the one just described, and that fully emerged 
females may be supposed, as a iis not t o copulate a second time. The 
following extracts from my notes refer € observed departures from this 
apparent rule and to the sensitiveness of the male to interruption. 
27th September, 1921: At 11.45 saw another male holding a рш» - 
before, but between the spiracles, though close to the left one. I put t 
couple in a phial half filled with water, and shook it violently dn Aem 
separated. the male made no further attempt to capture the female, 
which, in a quarter of an hour, completed her emergence without effort. 
I drained off the water and kept the couple under observation for an hour. 
Neither took the least notice of the other. 
I repeated these experiments several times on this and subsequent days, 
and never found that connection was resumed. I have also separated 
pairs just as copula was about to be established, and ida just after 
it had begun. With two exceptions, one of which is about to be referred 
to, they have remained indifferent to each other, and the females, re- 
moved to a tank containing a large number of hunting males, excited no 
goes 
the two exceptional cases of resumed copula just ке to 
е hypertrophy of the sexual instinct іп a.male. The п 
olona 2 
At 10.20 p.m. (3rd October, 1921) noticed in a mating-tank over which 
an electric light was placed two insects in full copula. I placed them in a 
phial with some water. They immediately ра. From the appear- 
ance of the female I judged that she had emerged some minutes before, and 
I supposed that copula had about come to an end. At 10.40, the phial 
aving for some five minutes been unobserved, I saw that renewal had taken 
place. I moved the phial to get it in a better light, and the insects again 
