Greta morgane, also called the "Thick-tipped Greta," is a day active ithomiine butterfly from the subfamily Ithomiinae. The length of the wings of this clearwing butterfly range from 56 to 58 mm. It is a common butterfly in Mexico, Middle-America, and the Caribbean. It has been recorded in 2004 as a stray in south Texas.
The caterpillar uses plants from the deadly nightshade family (Solanaceae) as hosts. Therefore, the Greta morgane has body fluids which are nauseating for birds, making them unattractive prey.
Source: en.wikipedia.org/wiki/Greta_morgane - 07.12.2011
The members of the species Greta look pretty similar and stand out by their lucent wings.