Vacuum-powered aspirator (Precision Plastics, Beltsville, MD, USA) for rapid transfer of large numbers of blood-fed flies from holding cages to ovipots: 1. Holding plate; 2. Aspirator lid with attached transfer and vacuum hoses; 3. Transfer port and transfer hose; 4. Vacuum port and vacuum hose; 5. A 500-ml ovipot nested in the depression of the holding plate; 6. Elastic securing cord hooked into screw eye ring on the holding plate. Arrows indicate the direction of air flow. (Photo by T. Rowland).