Insect identifier · Mosquitoes
How to identify a Western encephalitis mosquito
Culex tarsalis
· Also called culex tarsalis, western culex, west nile mosquito west, irrigation mosquito
In the West and on the Great Plains, dusk bites near irrigation and marshes often point to Culex tarsalis, an important West Nile mosquito.
Dusk, irrigation, pale band on the proboscis, West and Plains. Not a striped backyard Aedes. West Nile and encephalitis history is why the name is scary; most bites are still itch. Neurologic symptoms in season need urgent care. Side photo of the head is the ID shot.
What does a western encephalitis mosquito look like?
Brown mosquito with a broad pale band on the proboscis and pale rings on the legs. Most active at dusk in open country and irrigated agriculture — not a striped backyard Aedes.
Western encephalitis mosquito (Culex tarsalis) is Medium. Colors people notice: brown, white, black. Field marks: Broad pale band on the proboscis; Pale rings on the legs; Most active at dusk in open country; Associated with irrigated agriculture. It is found outdoor. If those marks are missing, open Northern house mosquito, Inland floodwater mosquito before you force this name. Search phrases that belong on this page include what a western encephalitis mosquito looks like and western encephalitis mosquito identification.
Identification marks
- Broad pale band on the proboscis
- Pale rings on the legs
- Most active at dusk in open country
- Associated with irrigated agriculture
Size: Medium
Colors: brown, white, black
Where: outdoor
What a typical western encephalitis mosquito bite looks like
Typical mosquito welt after evening time outdoors. Fever, stiff neck, or confusion in season is a medical issue, not an ID issue.
People searching “western encephalitis mosquito bite identification” want the pattern, not a single anonymous bump. Typical mosquito welt; often noticed after evening time outdoors in rural or suburban West. Immediate steps on this page: Wash and soothe; Use dusk protection in irrigated or wetland areas; See a clinician for fever, stiff neck, or confusion in season. This species does bite or sting people. Fever, spreading redness, trouble breathing, or a child with many stings is professional care.
If you were bitten
- Wash and soothe
- Use dusk protection in irrigated or wetland areas
- See a clinician for fever, stiff neck, or confusion in season
Western encephalitis mosquito vs Northern house mosquito
Look for the pale band on the proboscis. Eastern backyard tigers have a thorax stripe and bite by day. Culex tarsalis is a dusk, irrigation, and marsh mosquito of the West and Plains.
- Northern house mosquito identification (Culex pipiens)
- Inland floodwater mosquito identification (Aedes vexans)
Range and season
Western U.S. and Prairie Canada, late spring through early fall.
Irrigated farmland, prairie sloughs, and rural western suburbs at dusk.
A western and Great Plains species tied to irrigation and wetlands. Important in West Nile and western equine encephalitis cycles.
Late spring–early fall, peak midsummer evenings
Common questions
Where is Culex tarsalis found?
Much of the western U.S. and Prairie Canada, especially near irrigation and marshes.
Does it bite people?
Yes, though birds are important hosts. People get bitten at dusk in rural and suburban settings.
Is it a disease mosquito?
It is a key western vector of West Nile virus and historically western equine encephalitis.
What mosquito bites at dusk in the western U.S.?
Culex tarsalis is a common dusk biter near irrigation, marshes, and rural suburbs.
What mosquito bites at dusk in the West?
Culex tarsalis is a common dusk biter near irrigation and marshes.
Culex tarsalis vs Aedes?
Aedes often bite by day and show stripes. Tarsalis is dusk-active with a banded proboscis.