INTRODUCTION. 
The discovery that mosquitoes are agents in the transmission of certain dis- 
eases, and especially the discovery by Sir Ronald Ross, in 1898, that mos- 
quitoes are the agents in the transmission of malaria, aroused a widespread 
interest in these insects. Hitherto the Culicide had been treated by ento- 
mologists with the other flies, and, being regarded as unimportant members of 
the order Diptera, were not especially studied and only such species as happened 
to find their way into entomological collections were described by systematists. 
In the year 1902, when the Carnegie Institution of Washington began its im- 
portant work in aid of scientific research, the systematic and biological knowl- 
edge of American mosquitoes was slight. A bulletin published by the U. 8. 
Department of Agriculture in 1900 embodies our knowledge of the North Ameri- 
can mosquitoes at that time. Twenty-three species were distinguished in this 
bulletin, while a number of the descriptions by early writers remained unrecog- 
nized. For the first time, the full life-histories of two widely different species 
were given. In the same year Major George M. Giles, formerly naturalist of 
the Indian Marine Survey, published in London the first edition of his “ Hand- 
book of the Gnats or Mosquitoes,” which was the first attempt to bring together 
and codrdinate the knowledge of the mosquitoes of the world. This work in- 
cludes 48 species from North America and, although many of these were un- 
known to the author, the original descriptions were made available for students. 
In 1901 the British Museum of Natural History published the first two 
volumes of “ A Monograph of the Culicide of the World,” by F. V. Theobald. 
In this work, 69 species were treated as North American and West Indian, but a 
number of these had not been studied by the author. At about the same time a 
volume entitled “ Mosquitoes; How they Live; How they Carry Disease; How 
they are Classified ; How they may be Destroyed,” by L. 0. Howard, was pub- 
lished. In this book 25 species were recognized and classified in synoptic tables 
by D. W. Coquillett. Considerable space was given to discussions of the habits 
of mosquitoes, their function in the carriage of disease and to the subject of 
remedies. 
While considerable knowledge had accumulated about the habits of mosqui- 
toes in general, it became evident that the different species diverged widely in 
habits and detailed information on these points was needed. It is necessary to 
distinguish carefully in this respect. Only those species that are harmful to 
man, either as agents in the carriage of disease or as annoying by their bites, 
need to be considered in economic work. Much useless labor and expense can 
be avoided by an accurate knowledge of the habits of the species. For instance, 
Boyce (Mosquito or Man?, p. 96, 1909) refers to the mosquitoes living in crab- 
holes as “the chief nuisance in those houses which are situated near the sea,” 
and figures a tent for capturing these mosquitoes. Our observations prove that 
the crab-hole mosquitoes do not bite nor annoy man, and no consideration need 
therefore be given to their destruction. Again, the commonest mosquito during 
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