Navy Dropwing. Blouvalvlerkie
Trithemis furva (Karsch, 1899)
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- A Guide to Identification of Dropwings (Trithemis) in General
- A Guide to Identify Blue Dropwings (Genus Trithemis)
Trithemis furva, Navy Dropwing, Genus Trithemis, is medium sized and all dark blue with yellow facial markings.
Key identification features:
- Face light yellowish brown, dark brown and black.
- Eyes dark purplish brown, lighter below.
- Thorax and abdomen dark blue.
- Wings are clear with very small basal amber patch on hindwings.
- Both sexes the last Ax vein is mostly incomplete. This may vary from specimen to specimen where one wing Ax vein may be complete (probably the left) Pterostigmas brownish black, 3 mm.
- Yellowish with black markings.
- Thorax has black zigzag line alongside.
- Abdomen with narrow black stripe running along its top.
- Wings each slightly smoky around nodus and tip, hindwings with small basal splash.
- Pterostigmas yellowish brown, becoming dark brown with age.
Compared with other species:
- The Navy Dropwing, T. Furva and the Highlands Dropwing, Trithemis dorsalis, is virtually indistinguishable in the field.
- A guide however, is firstly the habitat, being usually rocky rivers at low elevations. Secondly pterostigmas that are usually all brownish black, with no white end-veins, and thirdly, a female which has a single zig-zaggy thoracic side stripe.
- Also, the blue of the male is not so colourful and more blackish than in T. dorsalis.
- It is essential to examine secondary genitalia, with scythe-like hamules and bristle tuft on anterior lamina.
Link to simmilar species
Trithemis donaldsoni (Denim Dropwing) Trithemis dorsalis (Highland Dropwing)
Distribution and habitat:
- Most of South Africa but with insufficient records for the Dry central parts.
- Mostly streams, but also rivers, in open landscapes and open areas in forest. Often with emergent vegetation and rocks.
- From 0 to 2500 m above sea level, but mostly below 2000.
- Mostly perches on rocks, where it looks almost blackish, or on twigs and reeds at water's edge.
- Female usually away from the water, among tall grass or small bushes.