SWARMS OF MALES 129 



mating-habits of two European species of Anopheles. Of Anopheles bifurcatus 

 it is said that " the males hover in small flights about the skirts of groves near 

 rivulets in the still evenings of June," and of Anopheles maculipennis, " these 

 also fly in small swarms in the evenings of June, when I have taken them paired 

 in the air." 



In their " Report of the malaria expedition to Nigeria " Annett, Dutton and 

 Elliott give a short note on the swarming of male Anopheles in west Africa. 



" But after sunset, clouds of mosquitoes were often observed flying and hover- 

 ing in characteristic flocks in the neighborhood of native huts, about eight feet 

 above the ground. On capturing and examining many of these, all were found to 

 be Anopheles males." 



F. C. Willcocks has recently published observations, made in Egypt, in the 

 vicinity of Cairo, on the mating-habits of several species of mosquitoes. He 

 points out the difference in behavior of the different species in an interesting 

 manner. 



" The aerial dances performed by male mosquitoes at sunset are perhaps 

 worthy of note. The males of Culex, spp. dance in columnar form, well in the 

 open, or in some cases, near or above bushes, and from fifteen to twenty feet from 

 the ground. Thousands of individuals may be present in one of these dances, 

 all in extremely rapid movements of limited range. They produce a very 

 audible hum. The males of Cellia \^=Anopheles~\ pharoensis dance as a rule 

 in the open, but much nearer to the ground than Culex, nor do they collect to- 

 gether in such large numbers. Their flight is also much slower. The aerial 

 dances of the males of Grabhamia [=A'edes^ willcochsii are again different. 

 They appear almost invariably to take place close to bushes, under trees or sheds ; 

 the males fly backwards and forwards with a slow and easy flight, about three 

 feet from the ground, columns not being formed. One rather striking fact con- 

 cerning these aerial dances is the comparatively small numbers of females which 

 join them in order to pair with the males." 



An overlooked paper by Wahlberg, published in 1848 (Ofversigt Kongl. 



Vetenskaps-Akad. Forhandl., v. 4, p. 257) describes the mating-habits of far 



northern mosquitoes, undoubtedly belonging to the genus Aedes, as follows : 



" It has been noted as strange, that the males of mosquitoes (Culex) are only 

 found in very small numbers in the extensive moors of the far north, where the 

 bloodsucking females surround and attack the traveller in numberless swarms. 



" Eev. Lsestadius of Karesuando has informed me that these males are often 

 found on the surface of the lakes, beaten down by rain or wind, in such endless 

 numbers, that, when blown ashore, they form thick windrows. 



" One wonders then why they are not observed more commonly together with 

 the females. 



" I have recently had opportunity to convince myself of the reason for this, 

 during my stay at the ' Great Oive ' mountain. On the top of this mountain we 

 were surrounded and pestered by female mosquitoes in great numbers, but not 

 a single male was observed until I became aware of a loud singing noise, which 

 on investigation was found to be produced by immense swarms of mosquitoes 

 high up in the air, dancing in separate flocks. 



" On examination these swarms were found to consist nearly exclusively of 

 males. 



" This indicates that the males of the Culex — like those of Chironomids and 

 some other non-biting gnats — keep to themselves in a higher stratum of the air, 



