Mystery Paederinae

  About 700 specimens of this species were collected from leaf litter in Great Smoky Mountains National Park. Collections were made in October 2006 and April 2007. We think it's in the genus Sunius but have yet to come up with a satisfactory species. Any ideas? Please email Mike at

NEW: See below for a list of Sunius in NA, a link to Casey 1905, and descriptions of species occurring in Eastern North America.




            from Nomina Insecta Nearctica


Sunius Curtis 1829

1. Sunius angulatum Casey 1886 (Caloderma) Western

2. Sunius angustatum Casey 1905 (Hemimedon) See Below

3. Sunius confluentum Say 1834 (Lathrobium) See Below

4. Sunius conjux Casey 1905 (Caloderma) Western

5. Sunius continens Casey 1886 (Caloderma) Western

6. Sunius contractum Casey 1886 (Caloderma) Western

7. Sunius cuneicollis Casey 1886 (Oligopterus) Western

8. Sunius curtipennis Scheerpeltz 1933 (Caloderma) Western

9. Sunius debilicornis Wollaston 1857 (Lithocharis) Adventive ?

10. Sunius exilis Casey 1905 (Caloderma) Western

11. Sunius fenderi Hatch 1957 (Sunius) Western ?

12. Sunius filum Casey 1905 (Oligopterus) Western

13. Sunius flexilis Casey 1905 (Oligopterus) Western

14. Sunius luculentum Casey 1886 (Caloderma) Western

15. Sunius mobile Casey 1886 (Caloderma) Western

16. Sunius mollis Casey 1905 (Caloderma) Western

17. Sunius peregrina Casey 1905 (Caloderma) Western

18. Sunius pollens Casey 1905 (Caloderma) Western

19. Sunius quadripennis Casey 1905 (Caloderma) Western

20. Sunius reductum Casey 1886 (Caloderma) Western

21. Sunius remotus Casey 1905 (Oligopterus) Western

22. Sunius rufipes Casey 1905 (Hemimedon) See Below

23. Sunius rugithorax Hatch 1957 (Sunius) Western ?

24. Sunius rugosum Casey 1886 (Caloderma) Western

25. Sunius semibrunnea Casey 1905 (Caloderma) Western

26. Sunius tantillum Casey 1886 (Caloderma) Western

27. Sunius testacea Casey 1905 (Lena) See Below


Casey T.L. 1905. A revision of the American Paederini. Transactions of the Academy of Science of St. Louis. 15(2):17–248.

Can be found at:


Casey 1905 p160

Hemimedon n. gen.

In general appearance the species of Hemimedon strikingly resemble the Pacific coast Oligopterus, but the likeness is in great part superficial, as shown by the generic characters of the table, the labrum being quite different in structure. The genus appears to be very circumscribed in habitat, and, so far as known, limited in range to the more southern parts of the Appalachian mountain system. The two species before me are mutually as closely allied as those of Oligopterus, but may possibly be recognized by the following characters : —

Sunius angustatum Casey 1905 p160 (Hemimedon)

Slender in form but similar in coloration and lustre [sic] to rufipes, the punctures of the head and pronotum less coarse and rather sparser, those of the latter notably feeble, of the elytra somewhat finer and denser but of the same character; head as long as wide, rather distinctly narrower than the prothorax, otherwise as in rufipes; prothorax much smaller, nearly as long as wide, only just visibly obtrapezoidal, the sides feebly arcuate and the angles rounded; elytra similar to those of rufipes, except that they are transverse, only very slightly narrower than the prothorax though much shorter. Length 3.2 mm.; width 0.45 mm. Virginia, — Mr. Ulke ………. angustum n. sp. [Spelling???]

Sunius rufipes Casey 1905 p160 (Hemimedon)

Stouter in form and parallel, feebly shining, blackish-piceous, the abdomen black, the legs and antennae dark rufous; head well developed but distinctly narrower than the prothorax, slightly wider than long, the sides parallel and straight, the angles rather narrowly rounded ; eyes at rather more than twice their own length from the base; punctures rather coarse and moderately dense; prothorax large and distinctly obtrapezoidal, the sides broadly, feebly arcuate, the angles well rounded, the punctures finer than those of the head, well separated, the sculpture tending toward longitudinal rugulation; elytra small, slightly narrower than the head, much shorter than wide and much narrower and very much shorter than the prothorax, the sides rather strongly diverging from base to apex, the surface finely but strongly, rather closely and asperately punctate. Length 3.1 mm.; width 0.55 mm. North Carolina (Highlands) and Virginia (Pennington Gap) ………………………. rufipes n. sp.

The gular sutures are widely separated, most narrowly so well to the front, rapidly diverging toward base and are generally subobliterated. The male sexual characters are feeble, the fifth ventral segment unmodified, the sixth having a rounded apical sinuation occupying almost the entire tip, rather more than three times as wide as deep, with the edge of the sinus concavely beveled, gradually more broadly so around the bottom of the sinuation.


Sunius confluentum Say 1834 (Lathrobium) [Casey 1905 p159]

 Trachysectus Csy.

This genus also has but a single known species, which is widely distributed throughout the colder parts of the North American continent, east of the Rocky Mountains. It may be readily known by its coarse and confluent sculpture and short tarsi, the first four joints of the posterior equal and the anterior slightly dilated : —

Rather stout, parallel, moderately convex, blackish-piceous, the elytra —rather broadly at tip,— antennae toward base and legs, rufous; prothorax also generally rufescent; surface feebly shining, densely sculptured, the head coarsely, with the punctures elongated by compression, the pronotum longitudinally rugose, the hairs borne from the minute granuliform punctules along the middle of the depressions or at the middle of the cephalic punctures, the punctures of the elytra sparser and smaller, asperate, of the abdomen extremely minute; head well developed, as wide as the elytra, a little wider than long, parallel and straight at the sides, the angles broadly rounded; eyes moderately developed, convex; prothorax much narrower than the head, obtrapezoidal, wider than long, the anterior angles obtuse but only slightly rounded; elytra quadrate, parallel, a fifth wider and two-fifths longer than the prothorax. Length 3.5 mm.; width 0.8 mm. Rhode Island and Virginia to Iowa and Minnesota ……........................................................................................…….  confluens Say

The male has very simple sexual characters, the fifth segment being unmodified and the sixth having a small triangular median emargination. The under surface of the head is as coarsely and densely sculptured as the upper and the gular sutures are rendered conspicuous by reason of the fact that the narrow space between them is highly polished, sculptureless and concave, gradually broadening near the base. The name confluens is an Erichsonian emendation of the originally published "confluenta” of Say, (= Lathrobium confluentum).


Sunius testacea Casey 1905 (Lena) [Casey 1905 p189]

 Lena Csy.

Although evidently allied to Pseudomedon by the structure of the labrum, gular sutures and hind tarsi, this genus departs widely in general facies, sculpture, in antennal structure and in its undilated anterior tarsi. The labrum is completely devoid of any trace of teeth but has a well developed median notch ; the gular sutures are moderately separated at the front of the under surface of the head but thence gradually diverge widely to the base. The antennae are somewhat as in Medonella, being very short, with the third joint shorter and narrower than the second, the shaft gradually becoming notably thicker or clavate toward tip. The posterior tarsi are moderately long, very slender and filiform, with the first four joints decreasing rapidly in length, the first almost as long as the next two combined, the fourth short, very oblique, extending slightly under the base of the fifth which is barely as long- as the first and much more slender. The single widely disseminated species is not rare under old leaves and rubbish and may be defined as follows :—

Moderately stout, somewhat convex, parallel, pale flavo-testaceous throughout, sometimes feebly picescent beneath and on the abdomen; surface feebly alutaceous from a very minute reticulation, the elytra and abdomen rather more shining and sparsely punctate, the former somewhat coarsely and subrugulosely, the head and pronotum not finely but extremely feebly and subobsoletely punctate; head well developed, somewhat wider than long, the sides parallel and nearly straight, the angles right and rather narrowly rounded; eyes moderately large; antennae short, about a fourth longer than the head in the female; prothorax distinctly narrower than the head, slightly transverse, distinctly obtrapezoidal, the sides straight, the angles obtuse and moderately rounded; elytra large, quadrate, much larger than the head, a fourth wider and one-third longer than the prothorax, parallel, the sides nearly straight, the basal angles right, but slightly rounded and rather widely exposed at base; abdomen parallel with the sides feebly arcuate, fully as wide as the elytra, the segments short, the fifth longer as usual. Length 2.0 mm. ; width 0.45 mm. Texas (Austin, Houston and Brownsville) and Florida (Enterprise) …………………………………..   testacea Csy .