Slide 60
The last two genera, Culiseta and Culex may be differentiated by the presence or absence of prespiracular bristles. Culiseta has prespiracular bristles. Culex does not. In most species of Culiseta the cross veins arising from wing vein four are close together. In Culex they are widely separated. Likewise, Culiseta has a row of bristles on the subcosta wing vein and Culex does not.