The Butterflies of North America Screen Saver and Wallpaper rotates 60 spectacular photos of colorful butterflies. All butterflies have been seen north of Mexico, as verified by the North American Butterfly Association's butterfly checklist. Optional captions let you display both the common and scientific names of each insect in your choice of font and screen position. You can also select up to 23 transition effects, show images full-screen or original size, and specify the length of time pictures appear on screen. System-tray and desktop-based screen-saver controls (which work with any screen saver) are part of this excellent package. You can enjoy this nag-free trial version for up to two weeks.