Synthetic blends of chemicals identified previously from human skin emanations were evaluated against mosquito and biting fly populations at the Lower Suwannee Wildlife Refuge near Cedar Key, FL. Mosquito Magnet™-Experimental traps were baited with the Red (400 ml acetone:10 ml 1-hexen-3-ol:10 ml 1-octen-3-ol), Blue (400 ml acetone:1 g/liter lactic acid:20 ml glycolic acid), or Green blend (400 ml acetone:1.5 g/liter lactic acid:20 ml dimethyl disulfide) plus CO₂ or with CO₂ alone (control). A relative index of efficacy was determined by dividing each mean blend trap catch by the mean control trap catch. Five mosquitoes (Aedes infirmatus, Ae. taeniorhynchus, Ae. triseriatus, Anopheles crucians, and Culex nigripalpus), 2 ceratopogonid (Culicoides floridensis and C. furens), and 1 tabanid (Diachlorus ferrugatus) and phlebotomine (Lutzomyia shannoni) species were trapped. The Red blend CO₂ treatment significantly increased collections of Ae. taeniorhynchus (3.4×), An. crucians (2.8×), total mosquitoes (2.7×), C. furens (17.6×), and L. shannoni (10.8×) compared with control traps. Traps baited with either the Blue or Green blends generally captured fewer insects than traps baited with the other 2 treatments. However, traps baited with the Green blend caught 7× as many C. furens as the control traps. Responses clearly varied according to species; therefore, “one size does not fit all” when it comes to attractant blends.