lampyridae
Lucidota atra, the black firefly. New York.
Not all fireflies luminesce. Lucidota atra is a day-flying species, common in eastern North America, with vestigial light-producing organs.
photo details: Canon MP-E 65mm 1-5x macro lens on a Canon EOS D60
ISO 100, 1/200 sec, f/13, flash diffused through tracing paper
Microphotus angustus - Pink Glowworm
California Coast Range
Believe it or not, this squishy pink thing is an adult beetle.
Now and again, evolution produces a species that loses the complexities of the adult form. These animals simply retain a larval appearance into their adult life, later gaining only the ability to mate and have offspring independent of the other trappings of maturity. Perhaps the adult traits of large eyes, large brains, long legs, and big wings are so expensive that just skipping all that extra development allows an animal to get on that much more efficiently with the…