29) 
I1V.—GeEnNus PSOROPHORA. 
Our single species is of a yellowish color, usually varied with brown, the bases of 
the tarsal joints white. It is considerably larger than any of our other species of 
yellowish or brown mosquitoes: 
ciliatus Fabr. 
conterrens Walker. 
molestus Wied. 
? rubidus Desv. 
V.—GeENUS MEGARHINUS. 
Our three species are among the largest in this family, and are not known to occur 
north of the District of Columbia. They may be separated as follows: 
Allitarsi: marked withswhite= =)... -2 2: = 22. NIRS eens SE EE eee rutilus Coq. 
Hind tarsi alone marked with white ----- aah ees ge es Boras A ask Pein as portoricensis Roeder. 
None ofthe tarsi marked with whites ==) ose ee hemorrhoidalis Fabr. 
VI.—Genus AEDES. 
Our two species are among the smallest of our mosquitoes, and have a 1 pale 
brownish ground color. They may be distinguished as follows: 
Thorax marked with a median violet blue stripe...........-.---- sapphirinus O. 8. 
‘Thorax destitute: of such a/stripe = 3 see ee a ee ee . fuscus O. S. 
THE BIOLOGY OF CULEX, WITH REMARKS UPON SOME OF THE SPECIES. 
It is tolerably certain that the life round of all of the species of the 
genus, Culex is practically the same. They will differ more or less in 
the character of the-water in which they preferably breed, and differ- 
ing in this respect, they will differ also in some degree in their pre- 
ferred food, which consists of all sorts of aquatic micro-organisms. 
Down to the time when the writer published his account of Culex 
pungens, in Bulletin No. 4, New Series, of this office, there was not 
in any published work a thoroughly satisfactory figure of a well- 
determined species of mosquito from the United States, or of its 
earlier stages. The statements quoted in the text-books and manuals 
dated back in general to the time of Réaumur—more than one hun- 
dred'and fifty years ago. Réaumur’s observations were made in the 
month of May upon a species (Culex pipiens) which does not occur in 
North America, and the observations were all made at Paris, so that 
statements as to the duration of the insect in any stage would be 
incorrect even for the same species in a warmer or esliiee locality. 
The following account of the life history of Culex pungens (fig. 1) is 
ee from the writer’s bulletin above cited: 
Life history of Culex pungens.—The operation of egg laying was 
not ers cas but it probably takes place in the very early morning 
hours. The eggs are laid in the usual boat-shaped mass, just as those 
of Culex pipiens, as described by Réaumur. We say boat-shaped mass, 
because that is the ordinary expression. As a matter of fact, however, 
the egg masses are of all sorts of shapes. The most common one is 
