SEXUAL ACTIVITIES 275 



Assistant Surgeon Grubbs, of the Public Health and Marine-Hospital Service, 

 in a paper entitled " Vessels as Carriers of Mosquitoes," published as Bulletin 

 No. 11 of the Yellow Fever Institute, which has been mentioned more fully on 

 another page of this volume, gives instances which seem to indicate that calopits 

 came aboard a schooner at Vera Cruz, the vessel lying half a mile from the shore ; 

 that another vessel had the same experience. But the evidence is not analyzed 

 and the probability of the mosquitoes being brought to the ship by lighters, 

 which at that time were used at Vera Cruz for the interchange of cargo, is not 

 taken into consideration. In the first of the instances mentioned it is stated 

 that mosquitoes came aboard "" in large quantities." Some of these were said to 

 be calopus, but it is not stated that all belonged to this species. It is possible 

 that Aedes toeniorhynchus, a common coast species, may have been mistaken for 

 Aedes calopus. 



MATING. 



E. G. Hinds, of Victoria, Texas, in a report submitted to one of the writers 

 (Howard) in the autumn of 1903 shows that with this species mating begins 

 when on the wing. It may, and usually is completed while still flying, but the 

 female frequently alights during the act and before its completion. The com- 

 plete act requires but the fraction of a minute. According to this observer, 

 females partly or fully fed seem more attractive to males than those which have 

 not fed at all. Copulation sometimes, perhaps usually, occurs before either sex 

 has fed. Males often alight on the dark colored clothing of a person sitting 

 quietly and watch their chance to pounce upon a female coming to feed. The 

 time of the greatest activity of copulation seems to be between 4 and 6 p. m. 

 A male may mate with several females. More than one batch of fertile eggs may 

 be laid without intervening fertilization. 



The French investigators found that temperature has a great influence on the 

 sexual activity of Aedes calopus. When the temperature rises above 25° C. 

 (77° F.) the males become very active and the females but rarely escape fertili- 

 zation. When the temperature ranges between 20° and 25° C. (68°-77° F.) 

 fertilization is still the rule and the proportion of unfertilized females is very 

 small, but below this the proportion of unfertilized females increases rapidly 

 with the reduction in temperature. 



Goeldi points out that wherever many of these mosquitoes are together, the 

 males tend to congregate apart in Little clouds of fifteen or twenty or more ; they 

 show a marked tendency to gather over prominent objects, as the corner of a 

 table or other salient parts of furniture, while the females are flying all about the 

 room. He has noticed that they will settle themselves on the upper parts of mos- 

 quito bars while the females are flying around under the bed or in the immediate 

 vicinity. "These are lookouts, salient points for watching and observation, 

 whence the males direct themselves against any female that happens to come into 

 their area of dominion." When a female approaches one of these groups of 

 males she is pounced upon, the male clasping the female from beneath. Goeldi 

 says " He unites himself to her from the lower side and permits her to carry him 

 with a slow heavy flight for a few seconds (two or three only), and then again 

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