FOOD DIFFERENCE OF SEXES 113 



flower-visitors the females suck blood. In these hsematophagous females the 

 nectar of flowers may be considered as a supplementary food which prevents 

 starvation when blood is not available. With the males nectar appears to be 

 the natural food. It is hardly to be supposed that species of mosquitoes limit 

 themselves to particular flowers, nor is there any structural modification that 

 would indicate adaptation to certain flowers, such as exist, for example, in the 

 flower-visiting Hymenoptera. The great diversity of flowers visited by mos- 

 quitoes bears this out. With the mosquitoes it is probably merely a question of 

 easy accessibility of the nectar and also of the season in which a particular 

 species of mosquito makes its appearance. As the appearance of many species of 

 mosquitoes is regulated by conditions of rainfall which vary from year to year, 

 the flowers available to a given species can not always be the same. 



"... In conclusion I wish to place on record an observation on Megarhinus 

 septentrionalis D. & K., our largest mosquito. On July 14 of this year I found 

 a female of this species at Glen Carlyn, Virginia, probing for honey upon a cyme 

 of Hydrangea arborescens L. The mosquitoes of the genus Megarhinus are so 

 rare that very little is known of their habits, but it appears quite certain that 

 they do not attack animals, indeed, their proboscis is unfit for piercing the skin. 

 Probably they feed wholly upon the nectar of flowers, but as they are very rare, 

 even in their proper home — the tropics, and wnthal very shy, it is not strange 

 that they have escaped observation." 



It is worthy of note that Eeaumur fed Cidex upon syrup and believed 

 that the greater part of them are contented with a diet of the sap of plants. 

 Mosquitoes have been observed to come to exposed honey in large numbers. 



There is a decided difference in the food of the male and female of most 

 mosquitoes. Goeldi, referring to this difference, says : 



" A curious phenomenon is the difference in the methods of alimentation be- 

 tween the mosquitoes of the male and female sexes. The former out of doors 

 seek ripe fruit and flowers, and when they visit our houses frequent the sugar 

 basin, coffee, tea, wine, soups, the cups and saucers and plates of our tables — all 

 sweet substances in a word — abstaining as a rule from drinking blood. The 

 females, participating up to a certain point in this diet, are at the same time 

 addicted to the vice of blood-sucking. They are blood-suckers by choice, which 

 harms us, and it is cliiefly against them that our hatred, the result of despera- 

 tion, is directed." 



Making experiments in this direction he found that out of thirty-seven mos- 

 quitoes captured in a sugar-bowl there were one female and one male of A'edes 

 calop'us and two females and thirty-three males of Culcx quinquefasdaius, 

 whereas, crushing, with one blow of his hand, a number of mosquitoes trying 

 to enter a mosquito bar, he found that he had killed twenty-three specimens of 

 Culex quinquejasciatus, all of which were females. 



Goeldi also calls attention to the attraction which perspiration has for the 

 yellow-fever mosquito, both males and females, and shows that males often alight 

 upon the skin and drink the perspiration. He believes that the biting mosquitoes 

 were originally attracted by perspiration and that the females have developed 

 into blood-drinkers while the males have preserved the original condition. It 

 may be that the few reported cases in which males have been supposed to bite 

 are based upon a faulty deduction, males being seen in a biting position but 

 only drinking the perspiration and perhaps slightly irritating the skin. 



