130 American Midland Naturalist Monograph No. 3 



DISTRIBUTION. — Throughout the United States and Southern Canada. It 

 also occurs in Mexico (114) and in Europe. Southern States: Alabama (170); 

 Arkansas (30); Florida and Georgia (52); Kentucky (140); Louisiana (52); 

 Mississippi (97); Missouri (70); North Carolina (166); South CaroUna and 

 Tennessee (96); Virginia (49). Other States: Cahfornia (67); Connecticut 

 (52); Delaware (106); District of Columbia (52); Ilhnois (42); Indiana 

 (39); Iowa (155, 156); Kansas (128); Maine, Maryland and Massachusetts 

 (52); Michigan (88); Minnesota (131); Montana (112); Nebraska (178); 

 New Hampshire, New Jersey, New York, and Ohio (52); Oklahoma (159); 

 Pennsylvania (8); Rhode Island (99); Texas (108); Utah (143); Vermont 

 (90) ; Wisconsin (48) . 



BIONOMICS. — Mansonia perturbans is primarly a night-biting mosquito, 

 most active during the early part of the night. Females occasionally feed during 

 daylight hours in shady places when their haunts are invaded. The adults are 

 strong fliers. They are troublesome pests in some localities and readily enter 

 human habitations. The females lay their eggs on the surface of the water in 

 areas containing a heavy growth of aquatic vegetation. After hatching, the 

 larvae descend to the bottom and attach themselves to the roots or stems of 

 plants by means of the modified siphon. The pupae also remain attached to 

 the plants by means of their respiratory trumpets until the adults are ready 

 to emerge, when they detach themselves and rise to the surface. The larvae 

 develop slowly and the winter is passed as immature or mature larvae, thus 

 emergence of the adults takes place in the spring and summer. The larvae 

 usually drop off their host plants when disturbed. 



Methods of collecting larvae of M. perturbans are described by McNeel 

 (109) and may be briefly summarized as follows: Pull up the host plant from 

 a small area and lay them aside, scoop up muck and debris from the area 

 from which the plants were removed and pour through a strainer. Transfer 

 the material in small quantities from the strainer to clear water in a white 

 enamel tray and examine carefully for the presence of larvae. 



Genus PsoROPHORA Robineau-Desvoidyl 



Psorophora Robineau-Desvoidy, 1827. Mem. Soc. d'Hist. Nat., 3:412. 



The genus Psorophora is widespread throughout North, Central, and South 

 America and nearby islands, and although it is more common in the tropics, it 

 extends well into the temperate regions. The females are vicious biters, but 

 little is known of their importance as vectors of human and animal diseases. 

 The larvae are found in temporary rain-filled and floodwater pools. The devel- 

 opment of the larvae is usually rapid. In general the eggs are able to withstand 

 long periods of drying. The genus is represented in the United States by 

 eleven species, belonging to the subgenera Psorophora, Janthinosoma and 

 Grabhamia. 



SALIENT CHARACTERS. — Adult: Spiracular and postspiracular bristles present. 

 Postnotum without setae. Squama fringed. Fork of vein 2 much shorter than 



1 Consult Dyar (1928), Edwards (1932) or Matheson (1944) for synonymy. 



