Download this Insect Bee Hummingbird PC Wallpaper Free in 1920X1080 (HD), 1280X720, 640X360 resolutions for commercial use, and without asking for attribution. Insects or Insecta are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; usually, insects comprise a class within the Arthropoda.