Additions and Corrections
for Epler's 1996 "Identification Manual for the Water Beetles of Florida"
(major revision 24 May 2005; last update 8 December 2007)

Two recent publications necessitate updating the species list for Florida once again. 

Miller, K.B. 2005. Revision of the New World and south-east Asian Vatellini (Coleoptera: Dytiscidae: Hydroporinae) and phylogenetic analysis of the tribe. Zool. J. Linnean Soc. 144: 415-510.  This paper reinstates Derovatellus floridanus as a full species. 

Bergsten, J. & K.B. Miller. 2005.  Taxonomic revision of the Holarctic diving beetle genus Acilius Leach (Coleoptera: Dytiscidae). Sys. Ent. 31: 145-197.  One new species, A. confusus Bergsten, is described from the northeast US; it was recorded from as far south as South Carolina.  I have a male and female of this species from Little Dry Creek in Jackson County.

p 3.5  -  The larva of Matus leechi has been described (Alarie & Butera 2003); it lacks the chelate fore and mid-legs, but possesses large flattened spine-like setae on the fore and mid tibiae and tarsi.  Change the first half of couplet 15 to read: “Fore and mid legs chelate (pincer-like) or with ventral row of large flattened spine-like setae on tibiae and tarsi ……………………………….  Matus”

p  3.6  -  See the revised key (click here for PDF file) for correctly keying the larvae of Laccophilus, Agabus/Platambus and Ilybius.

p 3.14  -  Heterosternuta, still not recorded from Florida, will key to couplet 35', not 34.  The bifid apex of the aedaegus will identify the genus.

p 3.21  -  Agabus has been split into Agabus and Platambus.  For adults, the two genera will separate at the first couplet, with Agabus going to couplet 2 and Platambus going to couplet 3. For larvae, they may separate at the first couplet – Agabus species would key to couplet two; Platambus species to couplet one.  Agabus aeruginosus Aubé has been split.  The species we have in Florida is now called Agabus xyztrus Larson.   The undescribed species referred to in the manual as Agabus sp. A, described as A. astrictovittatus Larson & Wolfe in Larson & Wolfe (1998), is now named Platambus astrictovittatus (Larson & Wolfe).  

p 3.23  -  The species Agaporomorphus dodgei Young has been moved to a new genus and is now called Hydrodytes dodgei (Young).  See Miller (2001).

pp 3.36-3.37  - Coptotomus lenticus Hilsenhoff is considered a subspecies of C. longulus LeConte by Larson et al. (2000); thus the species/subspecies in Florida is C. longulus lenticus Hilsenhoff.

pp 3.56-3.57  -  The Hydroporus oblitus group is established as a new genus, Hydrocolus Larson & Roughley.

pp 3.70-3.72  -  Liodessus affinis is a complex of species; the species we have in Florida is Liodessus noviaffinis Miller.  Liodessus fuscatus has been renamed L. crotchi Nilsson.

p 3.76  -  Couplet 1 of key should read: "Length less than 6.5 mm;" Under Notes on species, length for M. leechi should be 5.5-6.1 mm.

p 3.81  -  Couplet 7 should read: "Length < 4.1 mm;"

p 3.83  -  Couplet 13' should read: "Length larger, 3.1-4.6 mm;"

p 3.84  -  Couplet 22 should read: "Smaller, length 3.1-3.8 mm;"

p 3.85  -  Under Notes on species, length for N. asidytus should be 3.1-3.8 mm.

p 3.86  -  Length for N. hybridus should read: "around 3.5 mm"

p 3.90  -  The characters given for the separation of the larvae of Thermonectus basillaris and Th. ornaticollis will not work.  Wilson’s (1923) original description of the larvae was incorrect.  At this time larvae may be identified only to genus.


Larvae and adults of Oulimnius latiusculus (LeConte) have been collected in western Florida. In my elmid key the adult will key to couplet 4, Microcylloepus.  Oulimnius lacks the serrated lateral margins of the pronotum found on Microcylloepus.  Oulimnius is also more oval in shape and the tooth that clasps the epipleuron arises from the margin of the 4th abdominal sternite; in Microcylloepus this tooth arises from the 5th sternite.  Larvae of Oulimnius will key to couplet 7; they can be separated from Macronychus by the pleurae on abdominal segments 1-7.  Larvae are separated  from Gonielmis by the lack of dorsal, setal-bearing humps on the abdominal segments and by having the anterior and posterior portions of the mesopleural sclerites subequal - in Gonielmis the anterior mesopleural sclerite is much smaller and thinner than the posterior sclerite.

A second species of Oulimnius, O. nitidulus (LeConte) has been collected in the Panhandle from a stream on Eglin AFB.  The two species are easy to separate:

O. latiusculus - Length 1.50 mm; elytra with series of regular striae with equally sized pits.
O. nitidulus - Length 1.25 mm; elytra with irregular striae, with some pits much larger than others.


p. 8.3.   A recent examination of a Paracymus larva collected by Dana Denson (FDEP) has brought to my attention that the description of the larva by Richmond (1920) used in my larval key is incorrect.  As noted by Archangelsky (1997: 42), Richmond's larva was probably a Crenitis.  Thus, change couplet 11 (p. 8.3) to:

11 (10)    Mandible with 2 inner teeth; clypeus with 3 medial teeth ............................. Phaenonotum

11'          Mandible with 3 inner  teeth (proximal tooth very small); clypeus with 4 medial teeth  ...  12

12(11')   Mentum with anterior row of large setae; frontal sulcus lyriform  .....................   Paracymus

12'         Mentum without anterior row of large setae; frontal sulcus U-shaped ..................  Anacaena

Thus, the larva of Paracymus (diagnosis on p. 8.50) has a mandible with 3 inner teeth, clypeus with 4 medial teeth, mentum with an anterior ring of large setae, and a lyriform frontal sulcus. See Archangelsky (1997: figures 34, 35, 40, 41).

A new species of Enochrus has been described from the Southeast US.  Enochrus grossi Short was described in: Short, A.E.Z. 2003. Enochrus (Methydrus) grossi sp. n. from the Southeastern United States (Coleoptera: Hydrophilidae). Trans. Am. Ent. Soc. 129: 539-542.  In addition to material from several southeastern states, paratypes were designated from Flagler, Glades, Gulf, Liberty and Putnam counties in Florida.

This species will key to E. hamiltoni in my key (p. 8.26). It can be separated by the reduced pubescence, restricted to the basal 2/3, on the hind femur; in E. hamiltoni this pubescence covers most of the hind femur.  In addition, the apices of the parameres are bent outwards in E. grossi (straight back in E. hamiltoni).

p 8.27  -  The correct name for Enochrus perplexus is Enochrus fimbriatus (Melsheimer).  Although Gundersen (1977) recognized the synonymy of the two names, he chose the junior synonym and thus the incorrect name perplexus (LeConte).

p. 8.3  -  Because the ligula of Enochrus may sometimes not appear to be longer than the basal segment of the labial palp, insert this patch for couplet 8:

    8(7’)     Ligula shorter than or subequal to basal segment of labial palp  ..  8a
    8’         Ligula longer than basal segment of labial palp  ……………….  10

    8a(8)    Right mandible with 2 inner teeth; left mandible with one inner tooth  ..  Enochrus
    8a’        Both mandibles with 2 inner teeth  …………………………….  9

p 8.9    -   A caution for users: Couplet 11' should read "Mid and hind tibiae without a fringe of swimming setae (although setae may be present on mid and hind tarsi only)".  Users may mistakenly key Hydrobius to  couplet 12 because Hydrobius tumidus has fine natatory setae on its mid and hind tarsi but none on the tibiae.  Of course, Hydrobius will not fit the diagnosis for Berosus or Derallus!!

p 8.10  -  Couplet 13 should read “Maxillary palp short and stout, no more than length of antenna, with last segment at least as long as the preceding segment”

p 8.11  -  Couplet 17' should read "Mid and hind tarsi 4-segmented"

p 8.16  -  Berosus striatus (Say) is now called B. sayi Hansen

p 8.41  -  Makhan (2001)  recently established the new genus Rishihydroius, which includes several species formerly placed in Hydrochus. As far the SE US fauna is concerned, he included in the new genus Hydrochus callosus LeConte, which would become R. callosus (LeConte). Other Nearctic taxa included are R. brevitarsus (Knisch), R. currani (Brown), R. scabratus (Mulsant) and R. setosus (Leach). The taxa Hydrochus sp. 1 and H. sp. 2 from my manual would also be included in Rishihydroius.  HOWEVER - NOTE THAT NO HYDROPHILID WORKERS HAVE ACCEPTED MAKHAN’S NAMES OR CLASSIFICATIONS!!  Also note that the Hydrochidae is now considered a separate family, as are the Helophoridae.


p 12.2  -  I have recently reared several larvae of Ora texana; Dana Denson (FDEP) has reared several Scirtes orbiculatus. Larvae of the two genera are very similar, but can be separated by several characters.  Click here for a PDF sheet illustrating the differences.

Missing citation:

Musgrave, P.N. 1935.  A synopsis of the genus Helichus Erichson in the United States and Canada, with description of a new species (Coleoptera: Dryopidae).  Proc. Ent. Soc. Wash. 37: 137-145.

Recent publications of interest:

Alarie, Y. & F.J. Butera.  2003.  The larva of Matus leechi Young (Coleoptera: Adephaga: Dytiscidae): implications for the larval ground plan of the genus Matus Aubé.  Aquatic Insects 25: 63-70.

Archangelsky, M.  1997. Studies on the biology, ecology and systematics of the immature stages of New World Hydrophiloidea (Coleoptera: Staphyliniformia).  Ohio Biological Survey Bulletin New Series Vol. 12 No. 1. ix + 207pp.

Arnett, R.H., Jr. & M.C. Thomas (eds.). 2001.  American Beetles. Volume 1. Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia.  CRC Press.  Boca Raton, London, New York, Washington, D.C.  443 pp.

Bacon, M.A., E.H. Barman & B.P. White. 2000. Biology of Coptotomus lenticus (Coleoptera: Dytiscidae: Coptotominae) with a description of its mature larva. J. Elisha Mitchell Sci. Soc. 116: 75-81.

Barman, E.H., M.E. Blair & M.A. Bacon. 2001. Biology of Ilybius oblitus (Coleoptera: Dytiscidae) with a description of its mature larva and an evaluation of diagnostic characters for separation of southeastern Ilybius and Agabus larvae.  J. Elisha Mitchell Sci. Soc. 117: 81-89.

Ciegler, J.C. 2003.  Water Beetles of South Carolina (Coleoptera: Gyrinidae, Haliplidae, Noteridae, Dytiscidae, Hydrophilidae, Hydraenidae, Scirtidae, Elmidae, Dryopidae, Limnichidae, Heteroceridae, Psephenidae, Ptilodactylidae, and Chelonariidae). Biota of South Carolina, Vol. 3. Clemson University, Clemson, S.C. 207 pp.  Costs $40.00 (incl. S/H). It may be ordered online:
     Logon as GUEST and search the term "Biota".
     Or send check payable to Clemson University to: Public Service Bulletin Room, 96 Poole Agricultural Center, Clemson University, Clemson, SC 29634-0129

Hansen, M. 1999. Hydrophilodea (s. str.) (Coleoptera). In World Catalogue of Insects, Vol. 2: 1-416. Apollo Books, Stenstrup.

Larson, D.J., Alarie, Y. and Roughley, R.E. 2000.  Predaceous Diving Beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska.  National Research Council of Canada Research Press, Ottawa, Ontario, Canada, 982 pp. ISBN 0-660-17967-9. US $64.95.  For ordering info, go to:

Larson, D.J. & G.W. Wolfe. 1998. Revision of the North American Agabus (Coleoptera: Dytiscidae): the semivittatus group. Can. Ent. 130: 27-54.

Makhan, D. 2001.  A new genus Rishihydroius and three new Hydrochus species (Coleoptera: Hydrochidae) from Africa. Bangladesh J. Zool. 29: 83-95.

Miller, K.B. 1998. Revision of the Nearctic Liodessus affinis (Say 1823) species group (Coleoptera: Dytiscidae, Hydroporinae, Bidessini). Ent. scand. 29: 281-314.

Miller, K.B. 2001. On the phylogeny of the Dytiscidae (Insecta: Coleoptera) with emphasis on the morphology of the female reproductive tract.  Insect Syst. Evol. 32: 45-92

Nilsson, A.N. 2000. A new view on the generic classification of the Agabus-group of genera of the Agabini, aimed at solving the problem with a paraphyletic Agabus. Koleopterische Rundschau 70: 17-36.

Nilsson, A.N. 2001. Dytiscidae. In World Catalogue of Insects, Vol. 3: 1-395. Apollo Books, Stenstrup.

A major new work on Dytiscidae has been published:

Larson, D.J., Alarie, Y. and Roughley, R.E. 2000.  Predaceous Diving Beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with
emphasis on the fauna of Canada and Alaska.  National Research Council of Canada Research Press, Ottawa, Ontario, Canada, 982 pp.
ISBN 0-660-17967-9
64.95$ CAN, other countries 64.95$ US.

For ordering info, go to:

This publication is a MASTERPIECE!  Anybody seriously interested in Dytiscidae must obtain it!!



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