The relative attractiveness of Mosquito Magnet-X® suction traps baited with various combinations of the BG Lure, nonanal, 1-octen-3-ol (octenol), and carbon dioxide was evaluated against laboratory-reared female Aedes albopictus and Culex quinquefasciatus in semi–field trials in northwestern Florida. In the absence of carbon dioxide, traps baited with the BG Lure (comprised of ammonia, caproic acid, and lactic acid) collected just as many mosquitoes as traps baited with carbon dioxide only. The numbers of mosquitoes caught in traps baited with no carbon dioxide and only nonanal, octenol, or their combination with or without the BG Lure were generally depressed compared with traps baited with carbon dioxide alone. When these chemicals were combined with carbon dioxide, no significant difference existed in the abundance of either mosquito species caught compared with traps baited only with carbon dioxide. However, in one trial, the combination of BG Lure plus octenol and carbon dioxide resulted in nearly a 4-fold depression in Ae. albopictus collections compared with carbon dioxide–only baited traps. The reason for this discordance remains to be investigated.