Friday mystery object #337

Last week I gave you this impressive beetle to try your hand at identifying:



Now although it’s big and showy, beetles can be hard to identify because there are just so many of them and closely related species can be very hard to tell apart.

This one has distinctive elongated jaws that mark it as being one of the stag beetles (family Lucanidae), which narrows it down, although there are well over a thousand species in the family. This one is a little bigger than most and the jaws are relatively unbranched, with a cleft at the end of a relatively squared-off and downward deflected ‘antler’.

Those ‘antlers’ are used by the males to wrestle for access to females, who have much more sensibly sized jaws and are smaller. Effectively they’re doing the same thing as deer and this is a good example of how evolution can lead to similar trends in behaviour and even sexual dimorphism across very different animal groups.

I think this is Mesotopus tarandus Swederus, 1787 which is a species from West Africa that is becoming increasingly popular in the pet trade. It has slightly shorter ‘antlers’ than the other species (or possibly subspecies) in the same genus, M. regius.

As you probably know, I’m more familiar with vertebrate identification than insects, so I was fortunate to have my intern Esmeralda, who is a keen coleopterist helping narrow this down, although I’m pleased to congratulate jennifermacaire who was on the same track with her identification.

Another mystery next week!

Friday mystery object #335 answer

Last week I gave you this insect from Suffolk/Norfolk to have a go at identifying:


I thought that some of you would have a pretty good idea about what it might be, and I wasn’t mistaken.

Chris got in quickly with this cryptic clue:

I don’t want to be a snob but this entomological servant is much more common than the butler.

This was absolutely spot-on, so for those of you who don’t know what it relates to I’ll explain. The reference to a servant was an allusion to a Footman, which is the common name for this type of moth.  Chris also narrowed it down to the species by explaining that it was common – so the Common Footman Eilema lurideola (Zincken, 1817).

There are a variety of similar looking Footman moths, but the Common Footman can be distinguished by its slightly greenish grey first pair of wings that have a yellow edge, but a yellow second pair of wings, that you can just make out in the photograph showing the underside.

Well done to everyone who worked it out – more mysteries next week!

Friday mystery object #335

Every summer, museums get a flurry of requests for invertebrate identifications as the heat brings forth all things many-legged and winged. Here’s a specimen I found on a train in Suffolk (although it may have boarded in Norfolk) on the 1st July this year:


Apologies for the slightly rubbish photos – they were the best I could manage with my phone while on a moving train. Its total length was around 15mm or so.

I’m sure that some of the keen lepidopterists out there will know what it is, so perhaps you could make your suggestion with a cryptic clue in the comments below?

Have fun!

Friday mystery object #334 answer

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


It’s a type of beetle – so a member of the Coleoptera or “sheathe wing” as palfreyman1414 pointed out) – in the family Dermestidae (as Wouter van Gestel intimated) and the species is Reesa vespulae (Milliron, 1939) as Tony Irwin hinted at with his cryptic clue:

Sometimes attached to a mogg, this seems to belong to a diminutive scooter

There were several other nice cryptic suggestions in the comments section, plus some on Twitter, so very well done to everyone who worked out what this was.

The species gets the name vespulae from its affinity with wasp nests, where it feeds on dead wasps and the scraps of insects that the adult wasps feed their larvae, so they’re sometimes called the Wasp-nest dermestid.


The natural target of Reesa vespulae

These tiny beetles can strikes terror into the heart of a museum curator, since they are well adapted to feed on dried insect remains (of which we have huge numbers making up our collections) and they are parthenogenic – meaning that they reproduce without mating (only females of the species are known) and just one individual is all it takes to create a full-blown infestation.

Damage caused by a Reesa vespulae infestation

Damage caused by a Reesa vespulae infestation

You can tell them apart from some of the other dermestid beetles (many of which are also museum pests) because they have ‘hairy’ elytra (or wingcases) with a lighter coloured patch on each of their ‘shoulders’ (they’re not shoulders, but you probably get what I mean).

If you find one of these wee beasts in your collection, be afraid – be very afraid!

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:


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:


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:


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!