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Documenting Massachusetts Stylurus Species

Larval and Exuvia Identification

Don't be concerned about IDing exuvia correctly, Please gather exuvia from bridge abutments and along clean medium to large rivers and streams Place in dry container, Label with Date, location, collector's Name and contact information and send or deliver to us at Millers River Environmental Center or e-mail and we'll arrange for a pickup.

Web References for larval and exuvia ID

Odonates of Connecticut - Gomphidae Plates       Key to Stylurids of Michigan


For positive ID: 

The Massachusetts Natural Heritage and Endangered Species Program prefers that specimens are collected for each site.  Exuviae are the preferred form of vouchering a species per site, as they are relatively easy to identify and curate as well as find.  Exuviae can be pinned or placed in a vial and labeled.  Adults, or larvae, are also solid voucher material.  One specimen per site should be sent to MREC for inclusion in the NHESP data set and one can be kept per collector. participants in Operation Rubyspot are covered by the permit issued by the Massachusetts Division of Fisheries and Wildlife for this project. For details contact

All specimens should have the following information: state, county, town, locus (water-body, road intersection, or other directions), collector, date, and relevant notes.  We request that one specimen per site be sent to the NHESP as voucher material. 

Clear photographs of adults showing diagnostic characteristics are acceptable records, and labeled photographs, when available, should be attached to the Rare Animal Observation Form.

Photographing for Documentation

Entire body from side, with legs visible
Abdomen from top, and for males with terminal appendages clearly visible
Shoulder stripes from top
Males: Hamules Females: use above criteria


Measurements of the overall length, Abdominal Length, and length of hindwing are useful tools in Ode ID helping to distinguish these large clubtails from their smaller cousins
Click to Enlarge Images

Arrow Clubtail used for demo

Arrow Clubtail used for demo

Arrow Clubtail used for demo

Riverine Clubtails range in length from 1.7 to 1.9 inches (43 mm - 49 mm), with a wingspan averaging about 2. 4 inches (62 mm). Arrow Clubtails range in length from 2.1 to 2.55 inches (54 mm - 65 mm), with a wingspan averaging about 2.75 inches (70 mm). The males average somewhat larger than the females.

Adult Zebra Clubtails range from 2 to 2.3 inches (52 to 59 mm) in length. Although male and female Zebra Clubtails appear similar in their coloration, the female is slightly larger with a reduced “club.”