A dark and variable beetle. This variation is "alternata" with alternate interstices containing red stripes.
The striae bear lines of fine puncturations in good alignment.
Easily confused with Paropsisterna morio which has extremely fine to almost non existent striae punctiurations.
These beetles are crepuscular, at least in Victoria and retire under bark during daylight hours.
This beetle is Paropsisterna morio. It was found under bark of manna gum. It is entirely black sometimes with brown or lighter lines in the interstices (spaces between the striae). The elytra are highly nitid (glossy) and striae almost entirely lacking grooves. This beetle is variable in size but often large and elongate and very convex. I have seen one with a red neck (back of head) and assume it to be morio. I have not seen these except under bark. They are nocturnal and feed on large leaved eucalyptus such as manna gum. These glossy, black, nocturnal beetles feature foveau (large dints) on the pronotum, one on each side and this species also has a large crease in the elytral base directly behind these foveau. Paropsisterna morio is widespread from Tasmania to Queensland.
This is Paropsisterna lineata, a mostly black and highly nitid (glossy) beetle with a few consistent yellow lines along the striae. This is a nocturnal species and found in the daytime hiding in the gaps in stringy-bark bark. I have not found it on other species of eucalyptus. I have not found it except under bark. Also seen in Croydon, Ferntree Gully, the Basin and Tasmania.
This beetle is Paropsis erudita. It is a highly nitid (glossy) species found under bark of smooth barked eucalyptus spp. such as manna gum. This is the more scarce of the nocturnal leaf beetles in my experience and found only twice. Also seen at Wonga Park (Mt Lofty) and Healesville. It lacks striae grooves and puncturation is very fine. There are two very smart looking red diagonal lines on the combined elytra in the form of a chevron.
This beetle is Paropsisterna atalanta. A rotund and mottled leaf beetle with its widest part towards the rear. This beetle was found on Eucalyptus. It is variable beetle and this example demonstrates the black marks that are usually present on the apex of the elytra and also at the base (forward) near the suture (centre line of the elytra).
I have seen this beetle also at Frazer NP (Eildon) and Anglesea.
Keyed out & fits FoV description. Pith with airholes rules out most other contenders. Culms blue-green, soft, 2.5mm diameter, ~50-70 striations not strongly raised. Primary bract continuous with culm. 60cm tall in temporary wet area in dry forest.