Thallarcha sparsana

Fair Footman at Ainslie, ACT

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Identification history

Thallarcha sparsana	27 Apr 2020	ibaird
Thallarcha sparsana	27 Apr 2020	GlennCocking
Unidentified	23 Apr 2020	donhe
Thallarcha fusa	21 Apr 2020	jb2602

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8 comments

jb2602 wrote:

21 Apr 2020

Minor pectinations on antennae, not sure if this makes it a male or female. T. fusa male has long pectinations.

jb2602 wrote:

21 Apr 2020

T. sparsana is perhaps another contender.

donhe wrote:

22 Apr 2020

How does one distinguish these 2 species ?

jb2602 wrote:

22 Apr 2020

There is a discrepancy between what you have up on Butterfly House and the description of T. fusa provided on MOV CD fusa complex.pdf.

donhe wrote:

22 Apr 2020

There is a discrepancy between Hampson making a drawing of a T. fusa specimen from WA showing an extensive hindwing dark patch but in the text indicating that the patch and the cell marking are separate, and BOLD 's specimens showing a small dark patch on the hindwing and also occuring in the eastern states. The hindwing patch distinction is moot, as we have no direct view of the hindwings of this specimen. I suggest it is recorded as Thallarcha species.

ibaird wrote:

23 Apr 2020

My suggestion of T. fusa is based primarily on the similarity of this specimen with the majority of forewing patterns visible for this species on both the ALA and Bold Systems 4. Despite the very long pectinations on the antennae visible on the historic LBH drawing of T. fusa, our specimen looks consistent to the pectination length visible on specimens of this species on Bold Systems 4. The forewing pattern is variable and it is perhaps sexually dimorphic in wing pattern as suggested by the LBH images; but with respect to hindwing pattern as seen from above as perhaps being different in males and females, that does not seem to be borne out in the Bold Systems 4 specimens. That is, there is at least one specimen there with antenna pectinations and a hindwing pattern with the cell marking separate from a reduced terminal hindwing patch. However, the MOV CD fusa complex.pdf clearly shows a male T . fusa with the cell marking closely adjacent to the hindwing patch which is also consistent with the historical LBH drawing by G. Hampson.

ibaird wrote:

27 Apr 2020

Notwithstanding my comments T. fusa seems unlikely on the basis the pectinations on the male antennae are not long enough for T. fusa.

GlennCocking wrote:

27 Apr 2020

I tried to lodge a comment when I proposed T. sparsanqa, but it has gone missing. The photo well matches T. sparsana specimens that I've been looking at. The main points are that T. fusa has a broader transverse band across the middle of the forewing, and several dark spots basal of it. T. sparsana has a narrower band and only a single spot inside the transverse band. Both differences are visible in the LBH photos.

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