Glasswing Butterfly, Greta oto. A tropical butterfly. RANGE: Mexico to Panama. Black forewing apex broad with inner edge almost straight, white medial bar strong and bordering black apex. A common species with the Larval host plants being Cestrum lanatum, Cestrum racemosum and Cestrum sp. "San Luis." Owl Butterfly (Caligo eurilochus) "Tropical". The Owl butterfly is the largest and often the first butterfly that visitors encounter in a butterfly conservatory. Although the underside of all Owl butterflies always have eyespots and zigzag stripes, the upper sides are quite variable. The wing color varies from gray and brown to powdery blue, orange, and sometimes iridescent purple. These giants of the tropics are fruit feeders; they can be found in great numbers at the fruit trays in a conservatory. They live from five weeks to three months. Magic Wings Butterfly Conservatory, So. Deerfield, MA. USA.