58 MISC. PUBLICATION 336, U. S. DEPT. OF AGRICULTURE 
the summer. In the vicinity of Lake Apopka in central Florida, 
adults are present from March to December, a peak of abundance oc- 
curring in May or the last of April and a secondary peak the first 
part of August. Rearing experiments in artificial containers at 
Orlando have shown that, from eggs obtained in the spring, prac- 
tically all the larvae will have reached the fourth stage and some 
adults may emerge in about 3 months, but the remainder of the 
larvae go through until the next year. It appears, therefore, that a 
partial second brood occurs in this area. 
In northern localities larvae have been found associated with such 
plants as cattail (Zypha), aquatic sedges (Carex), pickerelweed 
(Pontederia), and swamp-loosestrife (Decodon, verticillatus). In 
Florida the principal host plant is the common pickerelweed (Ponte- 
deria cordata) (pl. 6, B). Larvae have also been collected, in vary- 
ing numbers, from the following plants, which are named in the 
approximate order of importance: Cattail (Typha latifolia and the 
rarer 7’. angustifolia), frog’s-bit (Limnobium spongia), waterlettuce 
(Pistia stratiotes), arrowhead (Sagittaria lancifolia and S. monte- 
vidensis), spatterdock (Vymphaeca macrophylla), and water-hyacinth 
(Piaropus crassipes) (124). Fortunately the water-hyacinth is not 
a favorable host plant. Otherwise the pest would undoubtedly be 
much more widely distributed and abundant in the extreme South, 
where the hyacinth covers large areas of lakes, bayous, and canals. 
A method for collecting the larvae is mentioned in the preceding 
discussion of the genus J/ansonéa. 
The females will bite readily during the daytime in shady, moist 
places, but the main flight takes place during the half hour just be- 
fore and after dark. Following this dispersion they are more active 
in the early part of the night than later. 
MANSONIA TITILLANS (Walk.) 
This is a tropical species and is found in the United States only in 
southern Florida. It closely resembles Mansonia perturbans, and the 
two are found in the same breeding places. The eggs are laid on the 
under surface of the leaves of waterlettuce, and the larvae and pupae 
have been found attached to the roots of this plant only. The adults 
may become fairly abundant and annoying locally. In 1933 larvae 
were taken in some numbers near the Saint Johns River at the latitude 
of Melbourne, but none could be found there the following year. 
Adults have been taken in light traps as far north as New Smyrna 
Beach on the coast, and several specimens have been collected in 
Orange County (latitude about 29°).° ‘This appears to be about the 
northern limit of its range, although its host plant occurs farther 
north. = 
Genus THEOBALDIA Neveu-Lemaire 
(Syn., Culiseta Felt, Culicella Felt, Olimacura H., D., and K.) 
Most of the species of this genus have a northerly range, and only 
two occur in the South, these two being very diverse in appearance, 
and neither of them important as a pest or as a disease carrier. The 
6In January 1942 they were taken at Leesburg, Fla., by T. E. McNeel. 
