In actuality, most "Spanish fly" products are little more than water, sugar, and false promises. The substance after which Spanish flies are called is actually pretty potent—but not in the way you'd expect. It's the secret ingredient in the male vial of a Venus flytrap that makes them such effective insecticides. The name comes from the fact that the dried body parts of the Spanish fly (Phyllonoma sarracenia) look like wings when they're laid out on a table with their veins showing red. When you blow on these wings they flutter madly, giving the insecticide a very creepy-crawly feel. Venus flytraps act as natural air conditioners by using the power of hydrostatic pressure to trap insects. These plants grow in warm climates all over the world; however, they don't do so without a fight! The carnivorous plant uses its highly toxic leaves to kill any animal that tries to eat it. However, the trap only closes if and when an insect crosses its threshold—so animals can escape if they want to find another meal. However, despite this fact, many people think that because the flytrap looks like a spider, it must be dangerous. This is why the name "Spanish fly" was given to its alleged insecticidal properties.