Friday mystery object #334

Happy Friday 13th! This week I have another diminutive animal (it’s a little under 4mm long) for you to have a go at identifying:

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I’m all too familiar with what this is and I’m sure that some of you have been unlucky enough to encounter them before, so cryptic clues as to the identity of this insect would be appreciated, for the sake of those lucky folk who avoided the attentions of this wee beastie.

Friday mystery object #333 answer

Last week I gave you this insect to have a go at identifying:

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I decided that this didn’t need a cryptic answer, since species in the Order of insects that this belongs to can be quite tricky to identify. The Order is of course the Diptera as this has two wings rather than the four most insects have – that means it’s a true fly (as palfreyman1414 pointed out).

Those pointy but sturdy mouthparts (unlike the pointy and skinny mouthparts of things like mosquitoes) give the family that this fly belongs to one of their common names – this is a type of “dagger fly” in the family Empididae – which you can tell from the antennae structure (three segments with the segment at the end being the longest). That helps narrow it down a little, but after that it’s a case of checking against things like wing veination and pattern – note the black line along the back.

Very well done to Emmanuel and James Bryant who noted these features and hit upon the correct genus. This specimen is Empis stercorea Linnaeus, 1761.

This specimen is actually mounted on a microscope slide, which makes it look a little weird:

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The label gives us the species, the sex (female) and the common name of “Corn-fly”, which I’ve seen used for a variety of fly species, but not for one of the Empididae. A bit of searching shows that this name is an old one used for Empis sp. in US catalogues for microscope equipment and mounted insects in the 18th Century.

There’s also a circular mark bearing a Wyvern (a two legged winged dragon), which is presumably a makers mark, although I’ve not yet managed to track down who the maker is.

More mysteries next week!

Friday mystery object #315 answer

Last week I gave you this big bug to identify:

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I had a feeling it would be fairly straightforward for some of you, since insects as big as this are reasonably distinctive, and I was therefore not disappointed with the flurry of correct identifications.

The first with a correct identification in the comments was Chris, who hinted at the scientific name with this suggestion:

Trying to identify this Cic-sac? Tho phar, Tho good! (Excuth the lithp!)

On social media people made suggestions relating to the common name for the species, mostly pointing out that it’s very loud. Putting the various hints together gives you the Double-drummer Cicada Thopha saccata (Fabricius, 1803).

Cicadas are weird. They’re in the Order Hemiptera (the true bugs) and the Suborder Homoptera (although that’s disputed and it’s probably safer to say Auchenorrhyncha). Best known for being noisy and having some species with synchronised emergence times that vary between every year and up to every 17 years, or somewhere in-between depending on species and environment. They have widely spaced eyes and a blunt head that is pretty distinctive.

As jennifermacaire pointed out regarding cicadas:

According to Plato, “[This species] used to be human beings who lived before the birth of the Muses. When the Muses were born and song was created for the first time, some of the people of that time were so overwhelmed with the pleasure of singing that they forgot to eat or drink; so they died without even realizing it. It is from them that the race of the [these insects] came into being; and, as a gift from the Muses, they have no need of nourishment once they are born. Instead, they immediately burst into song, without food or drink, until it is time for them to die. After they die, they go to the Muses and tell each one of them which mortals have honored her.”
– Phaedrus

The implications of this is that adult cicadas have a general inability to feed, although this isn’t quite true, since adult cicadas may still feed on sap.

This particular cicada is Australian and is one of the loudest insects on the planet, able to produce a call of over 120 decibels – loud enough to cause permanent hearing damage if right up against a human ear.

The abdomen is fairly hollow in the males of these insects, creating a resonating chamber, but sadly the last segment of this specimen has fallen off, making it hard to be sure of the gender on the basis of the genitals. However, the males have a couple of resonating sacs behind the hind-wing that is missing from this specimen, suggesting that it’s a female.

As far as noisy neighbours go, these insects are an occasional disruption, popping up every 4-6 years and making a noise that is apparently similar to high-pitched bagpipes.

It doesn’t sound great to me, so I’m (not so) secretly glad that I only have to deal with dead examples of these fascinating insects.

More mystery object fun next week!

Friday mystery object #315

It’s been another week of working with the Dead Zoo insect collection for me, so I thought I’d give you one of them to have a go at identifying:

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A big bug  at around 135mm wingtip to wingtip

I don’t think it’ll be particularly difficult for some of you, so please try to offer cryptic suggestions if you know what is, to keep it challenging for others who aren’t as familiar with these impressive invertebrates.

Have fun!

Friday mystery object #311 answer

For the last couple of weeks I’ve been offering up what has been affectionately nicknamed ‘cave snot’ for identification:

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The initial goop was a bit too difficult to identify from a photo, so I dug in and pulled out the critter responsible:

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This proved much more identifiable, with Chris immediately recognising that it’s the larva of a Caddisfly (not really a fly, but a more moth-like insect in the Order Trichoptera – which means ‘hairy wings’ as palfreyman1414 mentioned). Natalia Maas went one better by alluding to the family – the Philopotamidae or Finger-net Caddis, explaining the goop, which is actually made up of little silk nets shaped like fingers (hence the common name for the family). These nets are used to collect organic detritus and diatoms from flowing water, which the larvae then feed on.

I provided a couple of extra images to help narrow down the identification, since there are only five species in three genera of Finger-net Caddis in Ireland (and England for that matter), which are able to be differentiated from the anterior margin of their frontoclypeus (see the diagram below if you’re not sure what that is).

caddis-frontoclypeus

There’s an excellent website looking at Trichoptera in Ireland, descriptively called TrichopteraIreland, where you can find the details of how to tell the larvae of different genera apart, but the short version is to look at the frontoclypeus and if it has a deep U-shaped notch in it you have a Chimarra marginata, if it has a shallow V-shaped notch in it then you have Philopotamus montanus and if it’s a smooth curve then you have a species in the genus Wormaldia (which could be W. subnigra, W. mediana or W. occipitalis).

Unfortunately you can’t readily tell Wormaldia species apart when they’re larvae, so unless I’m missing a well-hidden notch in the frontoclypeus, we can’t identify this to anything better than genus level – but that’s still a substantial improvement on simply calling it cave snot.

I’ll be taking the specimen to the previous Entomology curator of the Museum, since his area of specialist interest is Caddis, so I’m sure he’ll be able to confirm the identification and I expect there may be some interest in where it came from.

More mysteries next week!