The following focus-stacked composite images show dorsal- and ventral views of the exuvia from a Common Sanddragon (Progomphus obscurus) larva that was collected and reared by Bob Perkins.

Common Sanddragon (P. obscurus) | exuvia (dorsal)
Here are some personal observations after examining the specimen carefully.
- Large eyes, shaped like Crescent Moons (as seen in face-head view).
- Hairy antennae.
- Lateral spines on abdominal segments five through nine (S5-9).
- Dorsal hooks on S2-9: prominent on S2, less prominent on S3; vestigial on S4-9.
- “Shoulder pads” on thorax.
- Cerci approximately one-third as long as paraprocts; epiproct and paraprocts about equal in length.

Common Sanddragon (P. obscurus) | exuvia (ventral)
The front- and middle legs block the mentum (prementum). This specimen is a good candidate for rehydrating the exuvia and reposing its legs.
Related Resource: Composite image: Progomphus obscurus exuvia.
Tech Tips
Six (6) photos were used to create the first focus stack; seven (7) photos were used for the second. A single focus point was positioned over select anatomical features, working from back-to-front; photos were taken at each point of interest.
The following equipment was used to shoot all of the photographs for the two focus-stacked composite images, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.
Adobe Photoshop CC 2017 was used to create the focus-stacked composite images, as well as spot-heal and sharpen the final output.
Copyright © 2019 Walter Sanford. All rights reserved.
Tags: cerci, Common Sanddragon dragonfly, dorsal hooks, epiproct, exuvia, gear talk, high-speed sync, larva, lateral spines, paraprocts, Progomphus obscurus, studio photography
Leave a Reply