8136_male_Côte-d'Or_17Jul07
Reverdin's Blue (Plebejus argyrognomon)
2011 photos highlighted in green. Click on any photo to go to an enlarged picture, or simply scroll down the page.
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| 8109_male_Côte-d'Or_17Jul07 | 27868_male_Côte-d'Or_26Jul11 | 8099_male_Côte-d'Or_17Jul07 |
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| 1916_female_Saône-et-Loire_11Jun06 | 20605_female_Côte-d'Or_11Jun10 |
8136_male_Côte-d'Or_17Jul07 |
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| 8096_male_Côte-d'Or_17Jul07 | 20601_female_Côte-d'Or_11Jun10 | 4004_female_Haute-Marne_17Aug06 |
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I first saw argyrognomon (couldn't it have a simpler name?) in 2001 in a field adjacent to a service station in central France, on our way south. It initially looked like idas/argus but had a much darker and deeper blue upperside differentiating it from both, although the specimen was rather worn. I have also seen argyrognomon at several places near Beaune in central France and at altitude near Isola, in 2006 in Italy, and in 2007 near Dijon and again near Digne les Bains, the most southerly location in which I have seen it. It tends to have an easterly European distribution and occurs in France mainly in the east, although there are some localities in the west and I saw it near Poitiers in 2008. |
The male underside ground colour is pale silvery-grey, almost white in some cases. The key characteristic is that the unh orange band is continuous, extending almost to the forewing costa, and the adjacent black unh “chevrons” are more rounded on the outside (idas is more v-shaped) and flatter on the side nearest the margin. It is generally considered to be similar to the Idas Blue (P. idas), although I would say that it would be difficult to confuse the two. |
| ref | sex |
observations |
alt. m |
| 8109 | M |
a male with quite pronounced uph marginal black spots. There is a very slight chequering of the fringes where the veins meet the margins. |
320 |
| 27868 | M | the shot captures very well the strong deep blue of the male argyrognomon upperside. | 320 |
| 8099 | M |
a male, with the uph margin unmarked by a series of black spots. |
320 |
| 1916 | F |
even allowing for the wear on 1916, it would be hard to recognise this female argyrognomon from the illustrations given in books, and a view of the underside is really necessary. There is an absence of any orange on the marginal lunules. |
380 |
| 20605 | F |
a relatively fresh female, with large and strong orange uph lunules. It is the same individual as 20601 as can be seen from the blade of grass it is resting on. |
320 |
| 8136 | M |
a typical male, with a strong continuous orange band, although only just reaching the forewing costa. |
320 |
| 8096 | M |
a male with generally reduced markings, such that the orange band is only just continuous. The silver studs are also much reduced and only s2 has more than a few silver scales. |
320 |
| 20601 | F |
the same female as 20605. Clearly a female as confirmed by the upperside, despite the silvery-grey ground colour which would strongly suggest male. This illustrates one the characteristics of argyrognomon, that the orange band is continuous and extends to the costa on both wings. The black chevrons are rather more sagittate than normal for argyrognomon. |
320 |
| 4004 | F |
a typical female underside, being pale brown. The silver in the studs shows up nicely in the shot. |
365 |
1916_female_Saône-et-Loire_11Jun06
20605_female_Côte-d'Or_11Jun10
20601_female_Côte-d'Or_11Jun10
4004_female_Haute-Marne_17Aug06
