FAMILY SPHINGIDAE
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Acosmeryx shervillii Boisduval sp. rev. 
Acosmeryx shervillii Boisduval, 1875, Hist. nat. Insectes, Spec, Gen. Lep., 1: 217.
Acosmeryx cinerea Butler, 1875, Proc. zool. Soc. Lond., 1875: 245.
Acosmeryx pseudonaga Butler, 1881, Illustr. typ
. Specimens Lep. Het. B. M., 5: 2.
Acosmeryx miskini brooksi Clark, 1922, Proc. New Engl. Zool. Club, 8: 11.


Acosmeryx shervillii (pseudonaga)
(.65 natural size)


Acosmeryx shervillii
(typical)
(.65 natural size)


Diagnosis.
See Acosmeryx anceus Stoll, and taxonomic notes below.

Taxonomic notes. This species is that referred to under A. socrates Boisduval by recent authors (e.g. Diehl, 1980; D'Abrera, 1986). Boisduval's types are in the Carnegie Museum, Pittsburg, but it has been possible to examine colour photographs of all the Acosmeryx. Typical socrates was described from the Philippines and also occurs in Sulawesi. It is intermediate in appearance between the two forms or species occuring in the rest of the Oriental Region. Both occur in Borneo and are illustrated here. Their geographical range is coincident, yet there are significant, constant differences in facies that led Kernbach (1967) and Diehl (1980) to treat them as distinct species.

One form is strikingly contrasted on the forewings and has a strong yellow discal spot, resembling a large but less red anceus (see also the description of hindwing differences in the diagnosis of anceus). The name pseudonaga Butler is applicable. 

The second form is typical shervillii, paler; greyer, with more crenulate, definite but finer forewing fasciae. The discal spot is smaller, with only a weak yellow centre. At the forewing margin the dark triangular zone posterior to the apical excavation is much narrower. The names cinerea Butler and brooksi Clark refer to this typical form.

The male genitalia offer no reliable distinction between the two forms, though there is variation in the shape and degree of spining of the harpe. Typical socrates from the Philippines and Sulawesi has the harpe smaller but deeper, more plate-like and less heavily spined than in more westerly populations. A. miskini Murray from New Guinea has the harpe slightly more elongate and irregular than in pseudonaga/shervillii. In all members of the complex the shape of the harpe is more irregular than in other Acosmeryx.

It is thus clear that Oriental populations from Sundaland westwards belong to a taxon or taxa distinct from typical socrates, for which the oldest name is shervillii, with the two forms referable to shervillii (= 
f. obliqua Dupont) and pseudonaga ( = f. cinerea sensu Dupont and f. obscura Dupont). The name shervillii has page priority over socrates; the latter name must be restricted to the Philippines and Sulawesi taxon.

Both forms were noted as larvae from the same host-plant at the same time by Dupont & Roepke (1941). It is therefore likely, considering this and the total geographical coincidence of the two forms, that they belong to a single, dimorphic species. This could be tested further by electrophoretic studies or breeding experiments. In Borneo f. shervillii is in the ratio of 1:4 with f. pseudonaga. There is no ecological segregation evident.

Geographical range. Indian Subregion to Sundaland; Philippines, Sulawesi.

Habitat preference. This is probably a general lowland species but was taken as high as 2600m on G. Kinabalu (Holloway, 1976). 

Biology. The larva was described and illustrated by Dupont & Roepke (1941). The young larva is green, spotted pale green, a dorsolateral band pale green over the anterior half, white posteriorly; abdominal segments have a brown dorsal patch. The horn is granulate, brownish black, upcurved. The full grown larva is green with pale brown dorsal patches. The thorax is swollen over Al.  The white dorsolateral line runs from A3 backwards, with a series of oblique yellow bars below it; a detached section runs obliquely over Al and A2. The horn is shorter, green, downcurved. In India (Bell & Scott, 1937) the dorsolateral line and thoracic flange are associated with reddish or plum colour, and the dorsal spots are of the latter shade. The larva illustrated by Semper (1896-1902) for typical socrates is also comparable.

Recorded host-plants (Bell & Scott, 1937; Dupont & Roepke, 1941; Barlow, 1982) are: Saurauia (Actinidaceae); Dillenia (Dilleniaceae); Leea (Leeaceae); Cayratia, Cissus, Vitis (Vitidaceae).

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