Trinodia

Trinodia
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Family:	Scarabaeidae
Subfamily:	Cetoniinae
Tribe:	Cremastocheilini
Genus:	Cremastocheilus
Subgenus:	Trinodia (Casey, 1915)
Type species
Cremastocheilus

Species of this subgenus of Cremastocheilus are most often found in the nests of Myrmecocystus.

Identification

Key to Trinodia species

This subgenus consists of twelve species; Cremastocheilus planipes, Cremastocheilus mentalis, Cremastocheilus saucius, Cremastocheilus quadricollis, Cremastocheilus setosifrons, Cremastocheilus hirsutus, Cremastocheilus excavatus, Cremastocheilus constricticollis, Cremastocheilus opaculus, Cremastocheilus spinifer, Cremastocheilus lengi and Cremastocheilus stathamae. Posterior angles of pronotum with inner margin raised and extending forward onto disc, dividing pronotal disc longitudinally into three unequal thirds; clypeus with a median carina, anterior angles with a deep incisure, forming in front an auriculate lobe. These areas contain exocrine glands which mediate interactions with ants.

Distribution

From Mexico City north to Wyoming, and southern California east to Texas. Includes Arizona, New Mexico, Colorado, Kansas and Nebraska.

Habitat

Desert, arid areas.

Biology

Host ants include: Pheidole, Myrmecocystus, Pogonomyrmex, Novomessor,

References

• Alpert, Gary D. 1994. A Comparative Study of the Symbiotic Relationship Between Beetles of the Genus Cremastocheilus (Coleoptera: Scarabaeidae) and their Host Ants (Hymenoptera:Formicidae). Sociobiology 25(1).

• Casey, T.L. 1915. Memoirs on the Coleoptera. The New Era Printing Company, Lancaster, PA. (6)pp. 340-370.

• Cazier, M.A. 1938. A generic revision of the North American Cremastocheilini with description of a new species (Coleoptera, Scarabaeidae). Bull. Southern California Acad. Sci, vol 37, pp. 80-87.

• Cazier M.A. 1940 New North American myrmecophilous Scarabaeidae Bulletin of the Brooklyn Entomological Society. Lancastar 35(4):122-133.

• Horn, G.H. 1871. Descriptions of New Coleoptera of the United States with Notes on Known Species. Trans. Amer. Ent. Soc. 111: 325-344.

• LeConte, J.L. 1866. New species of North American Coleoptera I. Smiths. Misc. Coll. VI., no 167: 81.

• Snelling, R. R. 1976. A revision of the honey ants, genus Myrmecocystus (Hymenoptera: Formicidae). Nat. Hist. Mus. Los Angel. Cty. Sci. Bull. 24: 1-163.