Till 
Introduction. 
The chief object of this work is to point out the different 
groups and species of mosquitoes, so as to help that large body 
of medical men who are working at such diseases as malaria, 
, yellow fever, &c., to attain to precision in the accounts and 
reports that they issue of the various experiments conducted 
with these insects. That certain species only of various genera 
carry the germs of certain diseases is probable, and thus it is 
important that the species as well as the genus should be 
identified. It is not enough to say that Ancphe 1 es carries malaria 
or exists in this or that place : we must note what species of 
Anopheles occurs. Moreover, I think much further investigation 
is required before we can place the blame of malaria-carrying on 
Anopheles alone. Other genera must be experimented with. 
There is nearly as much difference between Culex and Stegomyia, 
or Culex and Panoplites, as between Culex and Anopheles. In 
regard to the separation of numerous species previously included 
in Culex so as to form the genus Stegomyia there seems to be 
more justification than is afforded by structural difference alone : 
it appears that the two series of species differ in life-history. 
Yellow fever seems to have been traced to a member of the genus 
Stegomyia , and not to a typical Culex or Anopheles. 
Stegomyia fasciata, Fabricius, is chiefly abundant where 
yellow fever occurs, writes Dr. Lutz, who has also come to the 
same conclusion regarding its relation to that fever as the 
American Commission in Cuba. 
This work is only in an embryo stage, and some will certainly 
have to be remodelled. The time at my disposal has been so 
limited that I have been unable to go fully into such subjects as 
the variability of Culex fatigans, Wiedemann, and the complete 
synonymy of all the species. The non-piercing-mouthed group, 
Corethrina, I have paid little attention to : a few rare species that 
I have seen have been redescribed and figured; but I have 
neither had sufficient material nor time to remodel the two 
genera Corethra and Mochlonyx included in the group, nor have 
I seen the majority of them. Moreover, I feel very uncertain as 
to their true position. There are certainly characters in them 
common to the Culicidae and Chironomidae , and certain affinities 
to the Tipulidae, and I think their separation as a distinct 
family would be more satisfactory than their inclusion here. 
In conclusion, I must express my thanks to the Director of 
the British Museum (Professor E. Bay Lankester), for his general 
help and suggestions; to Mr. Waterhouse, of the staff of the 
