Cucubano

http://www.cienciapr.org/news_view.php?id=825

The cucubano is a species of click beetle native to the island of Puerto Rico. It is often confused with a firefly because both species emit light from its rear segment. Unlike fireflies however, the Cucubano can also emit light from its middle segment, thereby giving it the appearance of 2 "headlights" and one "backlight", which it can turn off independently.

Because light pollution interferes with their reproduction, they prefer rural areas without much development

Locations known to be its habitat are the rural areas and outskirts of the city of Adjuntas, located in the mountains.

They average about an inch in length.

A Puerto Rican firefly is called a Cucullo which is a true firefly, also native to Puerto Rico. Cucullos average half an inch in length. The color of both of these insects lights is bright green.