A GUIDE TO THE STUDY OF BRITISH WATERBUGS. 201 



when small pellets of earth are flung at them ; and when they 

 do skate away they always return before long to their old 

 position. 



The males of Gerris are most extraordinarily amorous, 

 remaining coupled to the females for a long time. If one 

 examines them during late spring or early summer, say June or 

 the beginning of July, one finds the majority pairing, nearly all 

 the solitary individuals being nymphs. The male rides upon the 

 female (which is noticeably the larger), sitting somewhat back, 

 the fore legs tightly gripping her around the mesopleura, the 

 fore tarsi converging strongly, being placed along the first 

 abdominal segment of the female, the middle and hind legs 

 being quiescent or moving about aimlessly. The male grips 

 the female so firmly in this position that one must employ some 

 force to tear him away from her, and retains his hold even when 

 the pair are lifted up from the water in the hand, the female 

 meantime leaping, skating, or climbing gaily on, as if she had 

 no such heavy encumbrance embarrassing her. 



Meinert* selected a pair of Gerris canalium, Duf. (= aptera, 

 Schumm., Meinert), and having placed them in a bowl gave them 

 a couple of duckings. They forthwith sank to the bottom, and 

 lay there some time motionless until he teased them, whereupon 

 they mounted perpendicularly to the surface ; but, although the 

 male helped in the ascent by swimming with his middle and 

 hind legs, upon this occasion, the female managed only to reach 

 the surface with her head, and the pair sank again to the bottom. 

 After ten minutes had elapsed the female was again teased, and 

 the pair began again to move, swimming under water for some 

 time. Shortly after the insects were taken from the water, and 

 allowed to dry. They were then placed in the bowl again, but 

 the female could not stand up on her legs, and the pair soon sank 

 deeper and deeper in the water, so that only part of the female 

 was above the surface. Hitherto the male had remained prac- 

 tically motionless (except for the few swimming movements 

 previously narrated), firmly affixed to the female; but after he 

 had floated about half an hour in this position, entirely sub- 

 merged, he became disgusted with his situation, and began to 

 loose his fore legs from their firm grip. Both now sank right 

 down, whereupon the male tore himself loose, and left the 

 female to lie on the bottom below, while he himself mounted up 

 to the surface, and crawled up from the water on a twig, which 

 was placed in it, by means of his fore legs. When he had gained 

 a tolerably lofty place, he began to dry and preen himself as best 



* I regret my knowledge of Danish is not so complete as I could wish, 

 and I have had some little difficulty in interpreting several phrases, the 

 learned author employing one or two words, at the meaning; of which I have 

 had to guess. I hope, however, that, checked by the few observations I have 

 had the opportunity to make, the account here given will be found sub- 

 stantially correct. 



