1 23 Parasitology Research Founded as Zeitschrift für Parasitenkunde ISSN 0932-0113 Parasitol Res DOI 10.1007/s00436-016-5218-8 Toxicity of 25 synthetic insecticides to the field population of Culex quinquefasciatus Say Rizwan Mustafa Shah, Mahbob Alam, Daniyal Ahmad, Muhammad Waqas, Qasim Ali, Muhammad Binyamin & Sarfraz Ali Shad