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Observed: 21st August 2010 By: nightflynightfly’s reputation in Invertebratesnightfly’s reputation in Invertebratesnightfly’s reputation in Invertebratesnightfly’s reputation in Invertebratesnightfly’s reputation in Invertebrates
21 August 2010 Grenaghen (80)
Species interactions

No interactions present.


nightfly's picture

Hi Inopinatus, I looked at H,

Hi Inopinatus,

I looked at H, radiatus and H. digitatus and going by the wing veining, this fly seemed to be more consistent with radiatus.



inopinatus's picture

wing venation

Hi nightfly,

As far as I know wing venation is not reliable for separating the species - my understanding is that the only objective difference is in the structure of the genitalia, although there are subtle and somewhat subjective differences in the wing shape. What reference material are you using to identify species?

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Inopinatus, forgive me if the

forgive me if the above response seems a little abrupt, it was posted in haste, I apologise for the nature of it.

You have really got me questioning the reliability of the illustrations in the book I refered to for seperating these 2 species. The illustrations are quite different. Being used to the reliability of using illustrations from 'Waring, Townsend and Lewington' for IDing moths, I took the illustrations in 'Greenhalgh and Ovenden' to be of equal reliability. This may turn out to be a grave error.

My above ID may turn out to have no basis whatsoever,

Thank you,


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Hi,I looked at the 2

I looked at the 2 illustrations in 'Freshwater Life' by Greenhalgh and Ovenden (2007).

As far as I could see there was a significant difference in the structure of the sections within the wing, and I took it to be diagnostic, but having said that, I might have put too much store in the illustrations.

I noticed a structural difference which I would much prefer to point out on an image than attempt to describe!
My attempt could be a bit poor.


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Freshwater life

Hi Cathal,

No problem, your response was not at all abrupt and no apology is necessary whatsoever.

Freshwater Life is an excellent book that I have used often, but not so much for species identification - I believe it is intended more as a general guide to the groups of animals living in freshwater. It can't cover everything - for example there are reckoned to be 199 species of caddis in the UK (with a new one discovered as recently as 2010!).

There is a new key to adult caddisflies that should be published this year - which I'm very much looking forward to as all of the current guides are quite out of date. The Field Studies Council produce a great little photographic guide to some of the more common and easily identifiable species, that you can order from their website for only about £3.75. Their AIDGAP guides are generally excellent - I'd recommend the Ephemeroptera guide too.

All the best

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Hi Inopinatus, Thanks very

Hi Inopinatus,

Thanks very much for these recommendations, yes I appreciate what you are talking about re the diversity of species, eg caddis and how using 1 book in particular as an IDing aid is not really going to be very effective. I look forward to seeing the forthcoming book on caddisflies. I suppose the book I refered to was the best guide to caddisflies Ive seen yet and I believed it to be a lot more comprehensive than it actually is!

I was a bit disappointed during the summer when trying to ID a limnephilus using online images. I found an image not unlike mine. I then found the same image under 3 different current scientific names.

One thing I would like to add (should have long before now) regarding the above photo. That fly was large. It was P grandis sized or very close to it. No joke, it was as big an example of this type of caddis as Ive seen, a real beauty.

I have for some years been trying to establish the species of a caddis at a small lake, it could be P.grandis, striata, or maybe even bipunctata? ALL could be present and Im quite sure Ive seen true P grandis, but there are others less readily IDed.

Maybe you could help me with some images?

Thanks for all the help and guidance,


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Do you have images of these? I don't have any pictures of them myself I'm afraid. Phryganea striata is now called Oligotrichia striata I believe, and the only recent records are from Scotland and Northern England (not to say that it isn't elsewhere though). Phryganea bipunctata and grandis can sometimes be seperated by the wing markings, with bipunctata typically having much more uniformly coloured wings - however these are highly variable.

There is an adult caddisfly occurence scheme receiving records of caddis. You can send a sample of the insect for identification in an airtight tube filled with alcohol of at least 40% (vodka/gin, etc. does fine for a few days of transit), with details of the collector, date and precise location. Details here:

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Hi Inopinatus, This is great

Hi Inopinatus,
This is great information. There is a network of small upland waters here and many caddis species hatch there. In early summer there are prolific hatches of chunky caddis. I am very curious to establish their species.

The largest examples I have seen are very mottled with contrasting tones on the forewings. There are prolific hatches of a slightly smaller caddis (still quite large) which are more monotone brown. I have a variety of images which I will post here in due course, hopefully IDs will be possible with some of the freshest specimens I have images of. I have often wondered am I seeing the same species at different waters which vary in size due to differing water quality, eg pH?

Without prattling on too much I should post a picture or 2. I will catch some specimens in the coming months and send them off for a thorough scientific identification, thanks for this info, its exactly what I have been hoping for.