Studies of egg rafts produced by Culex pipiens and Cx. restuans indicate presence of a longitudinal seam to be more typical of rafts produced by Cx. pipiens than by Cx. restuans. In 1982, rafts produced by Cx. pipiens were 56.8% seamed and Cx. restuans rafts were 11.7% seamed. Tested by chi-squared, the differences between species, and the seamed/unseamed raft ratio of each species had a p-value of 0.0001.