modified, adapted to life in subterranean

streams and aquifers. An example is the

North American Haideoporus texanus,

which, living in perpetual darkness, has

lost its eyes, pigmentation, and ability to

fly. It was first described in 1976, only

from San Marcos Pool of Edwards Aquifer

in Texas, and is regarded as critically

imperiled because of its small range, small

population (estimated at fewer than 10,000

individuals), and vulnerability to water

abstraction or pollution

species can be found together, because of subtle

differences in microhabitat.

The largest genus is Hydroporus, with around 200

described species and mostly marked in intricate

patterns of brown, black, and yellow. Many are

difficult to identify and need microscopic examination

or dissection (but can have differing ecological

requirements despite their morphological similarity).

Like a lot of Adephaga, aquatic or terrestrial, adults

produce defensive secretions, which can have a

distinct honeylike smell caused by phenyl acetic acid.

above | Nebrioporus elegans This widespread

European species of rivers and mountain streams

may, in fact, represent several species.

below | Haideoporus texanus The Edwards Aquifer

Diving Beetle, an endangered blind subterranean

species from Texas.