''Arsoa'' is a genus of

leaf beetle The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...

s in the subfamily

Eumolpinae The Eumolpinae are a subfamily of the leaf beetles, or Chrysomelidae. It is one of the largest subfamilies of leaf beetles, including more than 500 genera and 7000 species. They are oval, and convex in form, and measure up to 10 mm in size. ...

. It was first established by the French entomologist

Léon Fairmaire Léon Marc Herminie Fairmaire (29 June 1820 – 1 April 1906) was a French entomologist. A specialist in Coleoptera he assembled an immense collection comparable with that of Pierre François Marie Auguste Dejean (1780-1845). This is in the Mus� ...

in 1901, for two species described from

Androy Androy is the most southerly region of Madagascar. It covers an area of 19,540 km2, and had a population of 903,376 inhabitants in 2018. The administrative capital is Ambovombe-Androy, and the chief administrator is Michael Andrianirina (sinc ...

Plateau, in southern

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

. Adult males in the genus have very long forelegs. The genus was originally placed by Fairmaire in the family Clythridae (now known as the tribe

Clytrini The Clytrini are a tribe within the leaf beetle subfamily Cryptocephalinae, though historically they were often treated as a distinct subfamily, Clytrinae. As the other Cryptocephalinae, they belong to the group of case-bearing leaf beetles know ...

), near ''Miopristis''. However,

Martin Jacoby Martin Jacoby (12 April 1842, Altona – 24 December 1907, London) was a German entomologist who specialised in Coleoptera, especially Chrysomelidae (formerly known as Phytophaga). He was also a musician who played in the orchestra of the Royal ...

later determined that it actually belonged to

, and placed it in the "Edusinae" (now known as the section "Edusites" of the tribe

Eumolpini Eumolpini is a tribe of leaf beetles in the subfamily Eumolpinae. It is the largest tribe in the subfamily, with approximately 170 genera found worldwide. Members of the tribe almost always have a longitudinal median groove on the pygidium, which ...

), near ''

Abirus ''Abirus'' is a genus of leaf beetles in the subfamily Eumolpinae. It is distributed from the Malay Archipelago to the Indian subcontinent, China, and the Ryukyu Islands. The genus was first established by the Belgian entomologist Félicien ...

''.

Description

Adult males have very long forelegs that are slender and straight; the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

s are thicker, and are almost as long as the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

s. The head is the same width as the

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the ...

, and truncated in front. The antennae protrude a little from the middle of the body, are very slender, except the first segment, the third a little longer than the next, the last barely thicker. The thorax is slightly narrower than the

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs ( Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes altern ...

, very narrowed in the front with the posterior border bisinuated; these are almost cylindrical, or oval. The

prosternum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum (ventral), and the propleuron ( lateral) on ...

is truncated in front and at the base, very broad, the

mesosternum The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum ( dorsal), the mesosternum ( ventral), and the mesopleuron ( lateral ...

a little less. The intercoxal projection is rather broad and obtuse. The four hind legs are rather short and slender, the femurs a little thickened. The body is densely punctuated, more or less a greenish tan colour with dots and bands of whitish pubescence. The females are similar to the males, but have shorter forelegs and antennae.

Species

The genus ''Arsoa'' includes two species: * ''

Arsoa aranea ''Arsoa'' is a genus of leaf beetles in the subfamily Eumolpinae. It was first established by the French entomologist Léon Fairmaire in 1901, for two species described from Androy Plateau, in southern Madagascar. Adult males in the genus have ve ...

'' Fairmaire, 1901 * ''

Arsoa longimana ''Arsoa'' is a genus of leaf beetles in the subfamily Eumolpinae. It was first established by the French entomologist Léon Fairmaire in 1901, for two species described from Androy Plateau, in southern Madagascar. Adult males in the genus hav ...

'' Fairmaire, 1901

References

Eumolpinae Chrysomelidae genera Beetles of Africa Insects of Madagascar Taxa named by Léon Fairmaire Endemic fauna of Madagascar {{Eumolpinae-stub