ARBICO Organics Fly Eliminator Beneficial Insects, 4.5 UnitsRecommended if you own horses or other farm animals. Apply every 4 weeks This item ships free via USPS. ARBICO Organics Fly Eliminators are tiny, naturally occurring insects that feed on fly pupae. This predation disrupts the life cycle of the fly and causes their population to plummet. To get a clear picture of how they work it is important to understand the life cycle of the fly: The fly lays an egg that looks like a speck of sugar. Within hours,