126 MOSQUITOES OF NORTH AMERICA 
bushes, sign-posts, or even heads of grass, but others where the swarms hovered 
over paths through fields, or spots of different color but not elevated above the 
surroundings. The swarms over spots on the ground in all probability belong 
to different species from those attracted to prominent objects. Radl confesses 
that he made no attempt at close determination of the insects under observation 
and it is evident that he had no conception of the number of forms of similar but 
distinct habits that he might have before him. In consequence his statements 
are far too general and much that might have been used for or against his con- 
tention has escaped him. 
“Little as we yet know of the subject, it will be well to state right here that, 
even within the Culicide, there is not only a marked diversity in the mode of 
swarming of different species, but that there are many forms which do not 
swarm atall. In the case of the almost exclusively house-inhabiting Stegomyia 
calopus, as Goeldi has shown, there are no such swarms as in Culex proper. The 
males congregate in little groups of 15 or 20, hovering over the corner of a 
cabinet or other prominent object, and pounce upon the females that come within 
range. I can add that copulation frequently takes place when there is no evi- 
dence of even such weak swarms. It should be noted that in Stegomyia copula- 
tion takes place during the brightest part of the day. On the other hand I have 
upon two occasions observed small swarms of Stegomyia (presumably males) 
hovering over the heads of persons, in both cases shortly before sunset. Once 
this occurred upon the hotel veranda at Cordoba, Mexico, and again in the street 
at Acapulco, over the heads of passers and keeping along with them. In this 
case the meaning of the swarms would be hard to interpret. 
“ Upon a recent trip to the west coast Dr. H. G. Dyar found a pair of Culiseta 
consobrinus * in copula, resting on the under side of a board. This observation 
shows a wide departure from the short copulatory act of Culex and Stegomyia. 
“The crab-hole inhabiting Deinocerites cancer swarms during the short twi- 
light period just outside the crab-holes and copulation takes place then. 
“ Goeldi has given a vivid account of the swarming of the common house- 
mosquito of Para which he designates as Culex fatigans.t Swarming takes place 
indoors when it is nearly or quite dark and there are separate swarms of males 
and of females. Such peculiar mating-habits surely indicate a distinct species. 
In the case of our Culex pipiens the males are never found in houses—uniless, 
indeed, they happen to come from larve developed indoors. 
“My. E. A. Schwarz has kindly placed at my disposal his observations made 
on a species of Culex, probably the Culex cubensis of Bigot,t at Cayamas in 
Cuba. The swarming occurred in the house, always on the side away from the 
sun, and when it was almost fully dark. The mosquitoes could only be seen 
against the sky, when between the observer and the open doors and windows and 
close observation was impossible under the circumstances. However, the swarms 
in this case were made up of both sexes and copulation freely took place. A cap- 
ture of 60 specimens from such a swarm contains 44 males and 16 females.” 
In a later paper entitled “The Swarming of Anopheles punctipennis Say ” 
(Psyche, February, 1907), Knab published some novel observations on the 
swarming of the species mentioned. This is quoted: 
“Upon October 7 and 14 the writer observed the mating habits of Anopheles 
punctipennis and as, up to the present, nothing appears to have been made known 
*= Ouliseta inornatus, 
a eee. quinquefasciatus, The passage will be found in translation in the systematic part 
tThe specimens on which the observation was made have since been identified as Culex 
quinquefasctatus. 
