Pyrgus observations

These are observations on the white markings on the underside hindwings of the target seven species. The three bands of white markings and the marks in each of the spaces between the veins are shown here: Pyrgus wing diagram. Some of these markings appear consistent, some fall within a defined band, some are consistent with exceptions, while others appear quite inconsistent. Some examples are given on the page Pyrgus undersides chart ("the 7"). Information was collected in 2011 in the form of photos of many undersides (with photos of the uppersides to assist accurate identification), and this process is ongoing to build up a larger data bank; this may affirm the findings to date or prompt a reappraisal. Input is invited.

Marginal band:

s1/s2: these markings are nearly always sagittate or arch-shaped for all species. The shape and strength of the markings, and whether they are solid, seems reasonably consistent. s2 is usually the more prominent mark of the two. Alveus seems be consistent in being weak and amorphous here. Armoricanus seems to be consistently highly sagittate but is usually (but not always) not solid. Serratulae is always arch-shaped and appears to be always solid, but this is not necessarily definitive as other species can show solid marks here. Other species appear to be too variable here for any reliable ID pointer.

s3 and s6 postdiscal: there are usually smallish, rather amorphous, marks in the post-discal region of s3 and s6. These appear to be highly variable in terms of size and can often be almost absent. There appears to be no consistency except that serratulae usually has medium to large amorphous marks here.

v5: the rectangular marginal mark on v5 (half filling both s4 and s5) appears on all species. It appears to be a consistent indicator. The key elements seem to be the length, the neatness of the internal edge and whether it is washed over. The difference in length is quite subtle and requires some experience.

Carlinae appears to have a consistently long mark here, significantly longer than other species, although a number of carlinae were shown to have medium length marks, so it can be said that a long mark is indicative of carlinae but a medium length mark does not necessarily preclude carlinae. Carlinae usually has a neat internal edge. Alveus appears to be consistently short and usually with an amorphous internal edge. Cirsii is nearly always washed over with the reddish-brown ground colour, although this is also sometimes true for onopordi, albeit to a lesser extent.

Discal band:

s1: this "bump" appears to be surprisingly consistent. The key elements are the degree of roundedness and the extent to which the bump is leaning toward the basal region; in no case was a bump found to be leaning in the other direction. In two species the bump appears quite consistent and characteristic, almost a reliable ID indicator on its own.

For onopordi, the top half of the bump is noticeably shifted basally compared to the bottom half; this is often described as the "signe de Blachier" and is unique to this species and no other species appears similar. The bump of cirsii appears to be reasonably consistently tooth- or banana-shaped and strongly and regularly leaning basally. Serratulae seems to have a constant non-leaning bump, an apparently reliable pointer as no other species exhibited a non-leaning bump. The alveus bump seemed to be always noticeably leaning basally while the armoricanus bump seemed to be slightly leaning; quite a number of specimens were studied for this rather subtle feature to become apparent, and it may not prove consistent over time.

s2/s3: s2 appears to be inconsistent for most species, perhaps surprisingly given that s1 seems constant. It seems that armoricanus has a medium-sized rounded or amorphous mark in s2 whereas for carlinae it seemed to be consistently clear of any mark. Other species appeared to be too variable. The space in s3 discal is too small to be of relevance.

s4/5: the discal mark fills both s4 and s5. Onopordi seems to be the only species with a constant non-straight internal edge, and the mark is often described as anvil-shaped, although the mark is quite variable and can sometimes appear non-symmetrical. It is sufficiently different to other species to be considered a reliable indicator of onopordi on its own. The internal edge of armoricanus can sometimes be slightly concave while for other species the internal edge is usually straight.

The external edge varies from being almost straight, to extending slightly at the top, extending at both top and bottom, to almost concave. Serratulae seems consistent in having an almost straight external edge, and the mark is often wide, making a regular rectangle, and is often described as quadrangular. The external edges of armoricanus and cirsii seem consistently extended at the top and bottom externally, while armoricanus is sometimes extended at the top only. Otherwise, no clear indications can be made. Width seems to vary.

s6/7: this is effectively an extension of the key discal mark in s4/5. It has been examined with regard to its width in comparison to s4/5 and whether it is displaced internally or externally with regard to s4/5. There did not appear to be any consistent patterns emerging and therefore considered to be of limited value for ID purposes.

Basal band:

As can be seen from the Pyrgus wing diagram white marks only occur in three locations.

s1: this is too unclear to draw any conclusions.

s4/5: again, too unclear and too variable to suggest any constant indication.

s7: this mark is usually clear, but unfortunately seems to be rather inconsistent. A wide variety of types of mark occur here, in terms of width, roundedness of either side, and the angle at the external edge for marks that are near-rectangular, which can vary between 90 degrees and 120 degrees.

It is often quoted that serratulae has a neat round or oval mark here, possibly not touching the veins, or only tangentially, but it appears that some apparent serratulae (the degree of uncertainty is deliberate) have marks that are essentially rectangular but highly rounded where it meets the veins. Does this mean they are not serratulae? Or does it mean that the range of the serratulae mark here is not limited to the "classic" mark? Also, cirsii sometimes has marks here that are small and circular and would thus appear to be classic for serratulae.

Alveus, armoricanus and carlinae all appear to have broadly rectangular marks with essentially straight edges.

Colour:

Armoricanus seems to be consistently dark brown. Cirsii is usually a very distinct warm red-brown, sometimes very distinctly red. Alveus, carlinae and serratulae are a yellow-brown to a greater or lesser degree.

Veins:

The veins are clearly prominent in armoricanus, slightly so in cirsii, and to an extent in onopordi. In alveus they are clearly not prominent. The black edging of the marks (often referred to as a "marbling effect") is strongly characteristic of onopordi, although cirsii sometimes displays this effect to a lesser extent.