Discussion about genus Strepsigonia (Lepidoptera)


I would like to discuss about observations of Strepsigonia sp : 7 observations of S. affinis – /taxa/625440-Strepsigonia-affinis + 1 observation from me that I placed in S. placida (obs4) - /taxa/1158762-Strepsigonia-placida.

I would like to give you my opinion on these observations and then find out what you think.

Obs. from @chunxingwong (obs1) and @cclborneo (obs2): I confirm also S. affinis.

Obs. from @gancw1 (obs3 - /observations/9372606 ): I would like to say S. placida .

According to information found in the literature:

  • General shape: S. affinis has HW strongly angled as obs1 and 2 while S. placida has hindwing slightly angled for the female and not angled but with a tornus diagnostically produced for the male as obs3 and 4.
  • General coloration: S. placida is darker than S. affinis.
  • Pattern: the included space between the wavy line and the strongly dentate line at middle of costa on FW is pale rufous for S. affinis. S. placida is more uniform. For S. affinis there is a submarginal line pale and lunulate clearly visible on obs1 and 2 (as it is described in literature) but not on obs. 3 and 4.
  • Dots: HW with 2 black dots for S. affinis as obs1 and 2 and 3 black dots for S. placida as obs3 and 4 (on my obs the 3rd dot is a bit hidden by the hairs on the inner margin).
  • Distribution: S. placida has a wider distribution including Burma than S. affinis (restricted to Borneo and Malaysia). So I guess there is more chance that I can observe S. placida in Sumatra rather than S. affinis.

From all this information, i would say obs1 and 2 are S. affinis and obs 3 and 4 are both male S. placida.

Regarding the other observations of @gancw1 :

/observations/9372609 (obs5),
/observations/9372608 (obs6),
/observations/9372607 (obs7),
/observations/9372605 (obs8)

By the shape and general pattern (darker, 3 dots on HW …), i would say S. placida. But the color is not uniform and I cannot find any mention of the dark brown area on HW in the literature. So maybe Strepsigonia sp?

These are just my suggestions. I may be completely wrong, that’s why I would be happy to hear from your opinion and discuss it with you.


1 Like

Hello Nad, welcome to the Forum :)

Dear Nad,

I never thought that there would be discussion on understudied species like these Strepsigonia spp.

You have indeed done a marvelous job of compiling information and resources to distinguish between these two similar-looking species.

I agree that my observation and Chien Lee’s observation are indeed Strepsigonia affinis based on your points. The colours and patterns may be variable but wing shapes are quite fixed so the more angled hindwings and the closer gap between the hindwing tips does prove that the rest of the observations are definitely not S. affinis. However, the female of S. placida are strangely more similar looking to S. affinis with the less acute HW compared to the males.

Unfortunately, there are no comprehensive studies on Drepanids in Sumatra and the Malay Peninsular to safely identify those observations as S. placida. There could be other similar Strepsigonia species in those regions which may not be recorded yet. The long-term documentation of moths in Borneo has been done quite thoroughly by Dr. J.D. Holloway so his Moths Of Borneo website is quite complete, having all the Strepsigonia species of Borneo included. Although the specimen resolution is quite low, we could still identify S. affinis with it. S. placida is also recorded in Borneo so if only there are live specimen photos it from Borneo then we could compare them with the specimen photo.

In fact, the main reason most of these observations are misidentified as S. affinis is because of these wrongly used photo in jpmoth which appears as the top result on Google image:

These photos are in taken in Borneo so these means that these are in fact S. placida as there are no better Strepsigonia species match in Moths Of Borneo. It does look closer to your observation and the other observations. I would suggest that we should together suggest the S. placida in these observations you have mentioned, especially on the research grade ones.

Another thing we should do is contact the jpmoth team and also discuss with them on their S. placida photos used in their S. affinis page as they are an important source where many people refer too. Maybe good to have the thoughts of other Asian Lepidopterists as well like Roger Kendrick who is also on iNat.


1 Like

Thanks a lot :)

Dear Chun,

Thanks a lot for your answer.
I’m completely agree with you. So i will start to suggest new ID S. placida for the other obs. I already accepted the ID of S. affinis for your obs.

I didn’t mention the S. affinis of jpmoth in my first message because i had a big doubt about the ID. I thought also about an ID mistake and there is Strepsigonia sp. written below 2 of the 3 pictures… But i think you’re right and these 3 obs on jpmoth are certainly S. placida.


Answer from @gancw1


Hi Nad,
Henry Barlow has replied and he id my obs 5,6,7 and 8 as S. placida. This is his reply

There is 1 specimen in my collection which matches your first and third specimens.
It has been identified as S. placida Swinhoe. The plate in MOB8 is very poor and does not show adequate detail.
You can google Moths of Borneo for online access. Your second specimen may be more recently emerged."

I will update my observations with the new id

Best Wishes


I trust Henry Barlow. S. placida it is then!

I think now we are more confident to email jpmoth to correct the photos on their S. affinis page.

Hi Chun, Yes i’m agree with you. Can you help to write thise message ? Because my english level is not really good and i’ also don’t know all the technical vocabulary for Lepidoptera (just the basics) :)

Hi Nad.

Sorry, just got back from the field and finally enjoying some internet.

Sure I can write an email to JPMoth. Can I also include you in the email too?

@gancw1 you can also provide me your email address so I can include you as well in the email.


Yes i will send you my email adress in a private message :)
Happy new year !

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