New York Natural Heritage Program
Brook Snaketail
Ophiogomphus aspersus Morse, 1895
Insects

Identifying Characteristics [-]
Snaketails are characterized by their bright green thorax and are part of the Clubtail family. As their name suggests, Clubtails have an enlarged tip on the end of their abdomens, giving them a club-like appearance. The Brook Snaketail has narrow, brown stripes on its green thorax and has a black abdomen with yellow dorsal (top) markings (Needham et al. 2000, Nikula et al. 2003). Brook Snaketail adults have a bright green thorax with narrow, brown stripes. They are 1.7-1.9 inches in length. They have green eyes and, as with all Gomphids, their eyes are separated dorsally. Legs can be either all black or may have a pale stripe on the tibia. They have a slender, black abdomen with a moderately widened "club" at the end and yellow triangular dorsal markings on abdominal segments 2-8. Yellow, rounded side spots are present on abdominal segments 9 and 10. The terminal appendages of the male are yellow and distinctive in shape from other snaketails when examined under magnification. Female Brook Snaketails have thicker abdomens than males, and their subgenital plates are about two-thirds as long as abdominal segment 9.

Behavior [-]
Gomphid larvae spend much of their time burrowing into the substrate of streams and rivers where they are found. Adults can be found perching on the ground, on emergent rocks in streams and rivers, or on leaf surfaces (Nikula et al. 2003). They also use upland borders of streams for feeding and resting (Natural Heritage Endangered Species Program 2003). Adult females oviposit by tapping their abdomens onto the surface of swift-flowing water while simultaneously releasing eggs (Nikula et al. 2003, Mead 2003).

Diet [-]
Brook Snaketail larvae feed on smaller aquatic invertebrates and adults feed on insects which they capture in flight.
Brook Snaketail Images
click to enlarge
The Best Time to See
Adults are active from late April through late August but the best time to see them is probably June or July (Dunkle 2000, Nikula et al. 2003). Larvae may be found in appropriate aquatic habitats year-round.
J F M A M J J A S O N D
Present Reproducing
The time of year you would expect to find Brook Snaketail present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Maine Snaketail (Ophiogomphus mainensis)
    The dorsal abdominal markings found on the Maine Snaketail are more narrow than on the Brook Snaketail and are usually absent from abdominal segments 8 and 9 (Nikula et al. 2003). Male Maine Snaketails also have a more yellow club than Brook Snaketails (Dunkle 2000).
  • Boreal Snaketail (Ophiogomphus colubrinus)
    This species has black facial stripes which do not appear on the Brook Snaketail (Dunkle 2000).
  • Riffle Snaketail (Ophiogomphus carolus)
    The Riffle Snaketail has a whitish-green thorax and the dorsal spot on abdominal segment 8 is rectangular in shape, whereas the Brook Snaketail's thorax is a grass green color and the dorsal spot on segment 8 is triangular in shape (Dunkle 2000).