Thursday, 10 July 2014

Macromia - a truly wonderful genus

Over the last three weeks I have been roaming around northern Vietnam. It was truly productive, but how to put all that information in postings? For instance, how about the 37 gomphidia species? Or the bundle of Chlorogomphids (even if the season is as good as over for those beautiful fellows).  Or Macromia, for that matter? Karube (2011) mentions 6 species of Macromia (M. pinratani vietnamica, M. moorei, M. septima, M. urania, M. clio and M. cupricincta). As a matter of fact, over these 3 weeks I saw all of these and two more (M. unca and M. malleifera). There are still more species in Vietnam and it is important to have a close look at any that fly past.

Last year I only saw M. pinratani vietnamica and to my shame I have to admit that I came to recognize a reddish face as the telltale sign of that species. Beware! This is not correct. It is absolutely necessary to check a set of characteristics, but most importantly the shape of the hamulus and genital lobe. The presence or absence of facial markings, general coloration and shape of appendages form a set of characters that will in identification.

For the first time I saw a male of Macromia unca. It was hunting several meters high over the edge of a stream in the late afternoon, but well before females normally appear. Although this species was only recently described by Keith Wilson and only found this spring for the first time in Vietnam by Sebastien, it is fair to say this is a very common species in the hills of northern Vietnam. After having found it in Xuan Son NP, I also encountered it low in Tam Dao NP, and at various locations in Bac Kan Province, Ha Giang Province and Cao Bang Province. Invariably it appears in the last moments before dusk, to oviposit in streams while flying hurriedly in erratic flight over the surface.

Female Macromia unca, with generally brownish wings and characteristic markings in yellow on S2-3, long antehumeral stripe, smoked yellow labium and yellow sides to the the antefrons paired with the yellow postclypeus.

This is the male of Macromia unca. It shares the characteristics of the female, but has hyaline wings. In addition is has superior appendages well short of the epiproct and a hamulus that forms an impressive hook.
Of the reddish faced types, after M. pinrantani vietnamica, which has a very small genital lobe and is common, even very common, in Tam Dao for instance, M. moorei is the commonest. It has a much larger genital lobe, a hooked hamulus falling short of the lobe, and generally more yellow on S2, although this is variable. Its patterning is otherwise rather similar to M. pinrantani vietnamica. This was the common species of Pia Oac Nature Reserve.

Female Macromia moorei, showing reddish face and large yellow ring on S2.

Male of M. moorei, showing the large posterior oriented genital lobe. Note also the dorsum of S10, without a clear spike. In this specimen the ring on S2 is interrupted, like in pinratani.

Another male M. moorei, with a complete yellow ring on S2 and similarly the impressive genital lobe.
The second "other" red-faced Macromia we encountered was the much smaller M. septima. I am looking forward to seeing the male. For now we had to content ourselves with the female, which we found on both 24 and 25 June close to the T-junction of QL279 and TL212 in northern Bac Kan Province on a shallow stream.

This reddish faced small species, with amber wing bases, has a reddish dorsum to the thorax with yellow antehumeral stripes just surpassing the middle 
The other smaller species, of which I had already encounted in Tam Dao National Park, but for which until now I had not seen the male, is Macromia urania. This species has a blackish face with a smudgy yellow postclypeus. It has an English name, club-tailed skimmer, because of the expanded posterior segments, but this is in fact not that obvious. We encountered the female also close to the QL279 and TL212 junction in Bac Kan Province. The male was at km 58 of the TL257, south of Bang Lung.

This is a truly magnificent smaller species. The appendages are extraordinary compared to all other males displayed here, rounded and flat, whereas the hamule has a wavy outline, a character shared with a few closely related species (like septima).
Another brightly colored and large species that already featured in these pages is Macromia clio. Here both male and female. This is apparently a species that prefers a variety of habitats, from larger streams to brooks. We found it the male on the same stream that also produced the male M. urania, M. cupricincta and M. unca, along the TL257 in Bac Kan Province. Females were near the aforementioned junction.

Like the female the male of Macromia clio has a bright yellow band across the postclypeus and the blackish center of the labium bordered by a large yellow fringe. 
The female is a fine brightly colored insect, sharing the aforementioned characteristics of the male, but also with a heavily marked abdomen.
We are reaching the end of this parade of Macromia species. M. malleifera already featured in these pages and I still have only seen it in Xuan Son. But the last addition to the Macromia list was another red-faced species: Macromia cupricincta. I expected it to be much brighter reddish-brown, as its name suggests and as its depiction on Karube (2011) shows. Apparently it is not always that bright.

The male of Macromia cupricincta. In fact you can see the brownish color without yellow markings of S8-10, but it is very dark. One could overlook this, also because of the reddish face, as M. pinratani. But note the extreme curve of the wing at the anal triangle, indicative of this species, and the spike on the dorsum of S10.


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