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Genus Graphoderus

Predaceous Diving Beetle - Graphoderus occidentalis - female Larva - Graphoderus Predaceous Diving Beetle - Graphoderus perplexus - female Graphoderus perplexus Graphoderus perplexus Graphoderus liberus Graphoderus liberus?? - Graphoderus liberus Graphoderus liberus?? - Graphoderus liberus
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Adephaga (Ground and Water Beetles)
Family Dytiscidae (Predaceous Diving Beetles)
Subfamily Dytiscinae
Tribe Aciliini
Genus Graphoderus
Explanation of Names
Graphoderus Dejean 1833
Numbers
5 spp. in NA, 12 spp. total(1)
Size
10.4-15 mm(1)
Identification
Adults:
eyes unnotched at antennal bases
mid-femur with short setae (shorter than width of femur at its base)
males with 15-40 adhesive disks on the front tarsal palette: 2-3 large ones (at the base) + several smaller ones; no adhesive hairs (unlike Acilius)(1)
ground colour yellow; elytra with a black meshwork studded with numerous small pale spots or reticulation; pronotum and head yellow with or without black markings (1)
Larvae:
Similar in appearance and size to Acilius larvae but the ligula (palp-like structure located between the maxillary palps) is unifid/one-pronged compared to the bifid ligula in Acilius
Range
Primarily northern in distribution: transcontinental in Canada and most of the northern US; one species (G. liberus) ranges south to Florida in the east.
Habitat
In standing water (ponds, eutrophic lakes); prefers open, sun-warmed areas.
Season
all year, adults most often observed in spring and summer.
Food
predaceous on other insects
Life Cycle
univoltine(1)-adults overwinter and mate during spring; larvae develop and mature by early to mid summer.