Texas Fireflies

Field Guide: Fireflies of Texas

by Ben Pfeiffer

Texas is one of the most bio-diverse states in the continental US. A wide range of ecotypes – from wide open mountain ranges in the west, dense tall forests in the east, brush country of the south, and grasslands of the north – all contributing to extensive and exciting diversity in Texas’s firefly species. This field guide is the first attempt to document collectively the diversity of fireflies in Texas from a standpoint of both studying the morphological features but also documenting species specific behavior and flash patterns. This field guide is a work in progress, as new information is discovered it will be added here or updated frequently.


Quick ID: Central Texas firefly. Flashing 2 sec intervals at 76F. Flashes more often than P. pyralis. Shorter flight time than P. pyralis.
What to Look For: Look 18-27 minutes after sunset. Active for 20 minutes and then diminishing. Consider location and flash behavior as helpful for finding this species. Flashes of males are roughly 2 sec intervals, or longer if temperature is colder ( less than 72F).
Size: 9.3-12.5mm
Appearance: Easily confused with P. pyralis, as they are similar in form. Certain morphological characteristics help distinguish P. concisus from P. pyralis. Namely, entire surface of ventral segment 5 entirely black or brown versus a variable translucent-yellow apical margin in P. pyralis.
Flash Behaviors: Males: Flash pattern a single flash about 0.4 seconds in duration; emitted about every two seconds of flight.
Females: Flash response pattern a single flash about 0.6 seconds in duration and emitted approximately 0.6 seconds after beginning of male flash.
Temperature: 76°F – Flash every 2 seconds
Best Time: 18-27 minutes after sunset.
Habitat: Can vary. Typically oak hillsides, riparian corridors, and suburban lawns.
Distribution: Kerr, Comal, Uvalde, and Gillespie Co.


Quick ID: A small firefly of 5-7 mm in size. Emerges 30 min after dusk. Flash pattern is the best way to ID this firefly.
What to Look For: Commonly found with Photinus pyralis in the same habitat, but a lot less uncommon. Look for them 30 minutes after Photinus pyralis emerges. They fly moderately fast, lower to the ground, sometimes at the edges of a stream or bank. Their flash pattern is bimodal, which resembles a twinkle. Later as the evening progress they will fly higher in canopy.
Size: 5-7mm
Appearance: Triangular or roundish spot on head shield with two pinkish lobes on either side. Wing covers dark with thin pale yellow border. Can resemble a small Photinus pyralis, so flash pattern is often needed to ID.
Flash Behaviors: Fast flashes every 1.0, .08 seconds at 74°F. Bright twinkling flash as if bimodal. Females respond within 0.3-0.5 sec, single flash.
Temperature: 70°-85°F
Best Time: In June, 9:00pm - 10:00pm.
Habitat: Seems to prefer consistently wet muddy creeks and ephemeral streams in partially wooded areas in the Texas Hill Country. Likely able to colonize other areas but it is still undetermined as to its most preferable habitat. More susceptible to habitat changes and population decline than other species.
Distribution: Southern Oklahoma to Southern Texas. Does not reach southmost Texas.


Quick ID: The generalists of the firefly world.
What to Look For: ulpa de porro mam et adi ut hiliquia quamiorendunt, nime cus abo. Itatur am et adi ut hiliquia quam, of cimus, sequo tem.
Size: ulpa de porro ma
Appearance: ulpa de porro ma
Flash Behaviors: porro mam et adi ut hiliquia quamiorendunt, nime cus abo. Itatur am et adi ut hiliquia
Temperature: 87°F – Flash every 4 seconds
Best Time: ulpa de porro ma
Habitat: porro mam et adi ut hiliquia quamiorendunt, nime cus abo. Itatur am et adi ut hiliquia quam, of cimus. porro mam et adi ut hiliquia quamiorendunt, nime cus abo. Itatur am et adi ut hiliquia.
Distribution: porro mam et adi ut hiliquia quamiorendunt, nime cus abo. Itatur am et adi ut hiliquia


Flash Behaviors: Erratic in direction but consistent in intensity and length. Looks like little bolts of amber lightning streaking about sometimes over the tops of bushes, other times many feet in the air. Often seen perched on a branch, flashing single 1 sec. interval flashes. An active flyer earliest in the evening, while settling into a perched position later as flashing picks up from other fireflies. P. stellaris is a very reactive flasher - namely to the flashes of its own kind or even to the flashing of different species in the same area. This can cause very enjoyable flash "storms" that last up to an hour if weather conditions are ideal.


Quick ID: This is a test
Flash Behaviors: TEST
Temperature: TEST
Best Time: TEST
Habitat: TEST
Distribution: TEST