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Section O

This is for all the beetles that don't want to be pigeon holed, they are all fairly distinctive so hopefully should be easy to identify from pictures alone. 

Been looking for them in another section? LET ME KNOW and I can add them there as well if need be! 

Helophorus sp. 20 species

Family Helophoridae- grooved water scavenger beetles 


ID Features

  • clubbed antennae 

  • Metallic

  • Palps longer than antenna

  • Pronotum wder than long (transverse)

  • Pronotum with strong vertical grooves 

  • Heavily punctured elytra 

  • Y shape grove on head (Frons)

  • 1.7-7.0 mm


ID to species 

ID to species is an art and requires all manner of microscopic examination of both dorsal and underside characteristics, accurate sizing and shape of palps, in addition to the standard genitalia inspection.

For Keying I would recommend  Duff Vol 1. but there's also a Mikes's insect key as well, but for accurate identification, a reference collection would go a long way!


Cicones undatus

Family: Coldiidae

Associated with fungus infected wood 

ID Features

  • 2.3-3.5 mm

  • Dark to reddish brown body, head, pronotum and head

  • Elytra patterned with thick pale scales, often forming a zigzag pattern

  • almost circular club

  • Elytra NOT ribbed

  • Pronotum les transverse (wider than long when compared to Cicones varigatus and overall slighter in appearance

Fancy a key for comparison?

Mike's insect keys  has got you covered (You'll want Page 11, couplet 10)


Megatoma undulata

Family: Dermestidae


ID Features

  • 3.5-5.9mm

  • Black with white chevron scale markings (may be worn)

  • pronotum semicircular, almost triangular when viewed from above

  • 3 segmented club

  • often paler tarsal segments

Lots of good info, and more pictures at UKBeetles


Ptinus sexpunctatus

Family: Ptinidae


ID Features

  • 2.0-4.5 mm 

  • Light to dark brown in colour

  • Head usually hidden when viewed from above

  • Distinctive white markings made of pale scales 

  • Pale scutellum

  • Long filliform (threadlike) antennae

  • Underside covered with fine pale pubescence

Want some more info? UKBeetles has got you covered!


Female P.Fur showing pale markings and rounded body shape 

Ptinus fur

Family: Ptinidae


A sexually dimorphic species where the females are on average smaller, have thinner slender legs, and have a less rounded, more elongate appearance. This species may have white bands on the elytra (pictured left)

If there is any doubt key it out with Mikes's insect keys or use the excellent comparative images and info  at UKBeetles.

The males in particular look very similar to quite a few species 

ID Features

  • 2.0 - 4.5 mm 

  • May have patches of pale scales (pictured) but may be plain brown

  • antennae filiform (threadlike)

  • Antennae 3 quarters of body length in females, longer than the body in males 

Aulonium trisulcus


Family: Colydiidae


ID Features

  • 4.5-7mm

  • elongate and parallel-sided

  • dull brown with a slightly darker head

  • 2 vertical (longitudinal) furrows on elytra

  • Scutellum wider than long (transverse)

  • Believed to be associated with elm.


Sphindus dubius

Family: Sphindidae


ID Features

  • 1.8-2.0 mm

  • shiny, dark brown

  • Pronotum strongly punctured, broadest just before elytra

  • Pronotal edges, narrow, pale, and finely scalloped (crenulate)

  • Head wider than long (transverse)

  • Lighter shoulders to elytra

  • All tarsal segments narrow, lacking lobes, last (terminal) segment as long as all others combined

  • Pronotum and elytra with fine pale hairs (pubescence)

  • July - Sept



Atomaria linearis

Family: Cryptophagidae

There are lots of similiar species in the UK and personally I would recommend keying them out for an accurate identification. 

Mike has keys for them and other related groups available HERE


ID Features

  • 1.2 -1.5mmbrown, covered in fine pale hairs that lie plat (recumbant pubescence)

  • narrow and parallel sided

  • eyes touch the front margins of pronotum

  • Head wider than long (transverse)

  • Centre of pronotum (Disc) closely punctured

  • Scutellum much wider than ling (transverse)

  • Complete lack of strae on elytra

  • Antenna and legs paler than the body 

  • March- October 



Opilo mollis


Family: Cleridae

A predator of small wood boring beetles, typically associated with decaying wood  and bracket fungi in ancient woodlands, pasture woodland and fens (Duff, 2020)


ID Features

  • Uniformly thick threadlike antennae 

  • Elytra dark brwn with pale yellow patches

  • Elytral puncture rows fading towards the end of elytra 

  • Upperside covered in long pale hairs

  • Red legs and antenna

  • 8-13 mm

  • Jan-February, April - November


Xyleborus monographus


Family: Curculionidae, Scolytinae

There are lots of similiar species in the UK and personally I would recommend keying them out for an accurate identification. 

Scoltidines are typically small with paddle or tear drop shapped antennal clubs and many display a 'hooded appearence', covering the head completely from above. Often they are very hairy  and display 'flared looking legs. Associated with timber and include many economically destructive species 


Euglenes oculatus


Family: Aderidae

Associated with old and rotten Oak wood 


ID Features

  • Non clubbed, but thick, slightly saw edge looking antennae 

  • Third antennal segment longer than the second

  • Elytra widest behind its middle

  • Brown to light brown with slightly lighter appendages (femora darker)

  • March to October, December 

  • 2.1-2.6


Dyschirius sp.


Family: Carabidae

11 British species, with only 7 found in Ireland (Luff 2007). Small beetles with an obvious pinched in the waist that looks superficially like Clivina spp.(which can be separated by continuous obvious punctures around the edge of the elytra and a complete border on the edge of the pronotum). 

These are associated with burrows of other species and are actually fossorial in nature, so will likely be a fairly uncommon visitor to moth traps.


ID Features

  • Dark brown to brassy black 

  • Pronged front tibiae 

  • Obvious thin waist

  • Almost spherical pronotum 

  • 3.1-4.9 mm

  • May - July 


 Elmis aenea


Family: Elmidae 


Riffle beetles 

These small, long-legged, often metallic beetles are often found on moist rocks and moss-submerged wood and decaying vegetation in good-quality steams rivers and lakes. despite their aquatic lifestyles, these beetles cannot swim but instead crawl along submerged feeding on aquatic vegetation. Although some forms may lack fully formed wings, fully winged individuals may take part in dispersal flights and be attracted to light mistaken for the reflection of water bodies. 

The Genus Elmis (which only consists of one Species in the UK)  is separated from others in this family by the Characteristic 'U'; shape on the pronotum formed by the two parallel grooves of the pronotum  joined by a third horizontal groove (seen clearly in the first image)

Elmis aenea

ID Features

  • Clear 'U' shape on the pronotum

  • Body black with a metallic bronze elytra

  • Dark appendages 

  • Antennal bases and tarsi reddish in colour

  • Pinched appearance to the end of elytra

  • 1.9-2.2 mm

  • All year round 

Not quite right?

Try Mikes Key to the British Elmidae 

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