3. Observations on Mimicry in Bornean Insects. 

 By R. Shelford, B.A., Curator of the Sarav)ak Museum. 



[Arranged and communicated by Edward B. Poulton, M.A., F.R.S., Fellow of 

 Jesus College, Oxford, and Hope Professor of Zoology in the University.] 



The following paper is an abstract of results obtained by Mr. R. Shelford, 

 B.A., Curator of the Sarawak Museum, British North Borneo. The vast majority 

 of his observations were made at or near Kuching, the capital of Sarawak ; a few, 

 however, in Singapore. When no locality is mentioned, Sarawak is to be under- 

 stood. The observations form a very important addition to our knowledge of 

 mimicry in Malayan insects, especially the Coleoptera. 



Among Lepidoptera an Elymnias, believed to be a new species from Mount 

 Penrissen, is a tolerable mimic of the well-known Eupl(ea, Tronya crameri. 

 Among the Chalcosid moths, three species of Isbarta mimicked two of Euplosa and 

 one of PierirKS {Delias cathara). The latter is of considerable interest, inasmuch 

 as the Pierine model appears to be excessively rare. There can be little doubt, 

 however, as to the true relationship, for another species of the same genus, 

 I. pandemia, m a magnificeut mimic of another species of Delias {D. pandemia), 

 both coming from Mount Kina Balu in North Borneo. 



In the Neuroptera the Mantispides are shown to be mimics, a splendid new 

 species {M. simulatrix, McLachlan) resembling a common Bracon flying with it 

 on Mount Matang, near Kuching, while a small species from Singapore (3/. ? cora) 

 exactly mimicked an ichneumon flying with it. 



It is in the Bornean Coleoptera, and especially the Longicornia, that by far 

 the largest additions to the subject of mimicry have been made. Many Longicorn 

 species, chiefly of the genus Oherea, were excellent mimics of the Braconida, 

 and perhaps other Hymenoptera. The long narrow form of the beetle resembled 

 the Bracon at rest with wings folded. As seen from the side, certain species of Oherea, 

 notwithstanding their uniform diameter, were apparently 'waisted' like a Hymeno- 

 pterous insect, the efl'ect being due to a conspicuous white patch on the side of the 

 anterior abdominal segment s. The part of the body thus covered is obliterated, while 

 the outline of the patch is such that the uncovered, and therefore conspicuous, part 

 of the body conforms to the shape of a slender 'waist,' from the posterior end of 

 which the abdomen gradually swells. The efl'ect in one species is as perfect as if 

 an artist had deliberately painted the proflle of a Hymenopterous abdomen upon 

 that of a beetle. Among other examples of the same form of mimicry was a 

 magnificent Cerambycid from Mount Penrissen (Nothopeits or u. gen., n. sp.), a 

 beautiful mimic of the abundant wasp, Salius sericosoma, which flew with it. 

 The common Dammar Bee {Triyona apicalis), which does not sting, but is 

 formidable because of its bite, is the centre of a group of three species with the 

 most remote affinities. Not only is there a Longicorn, Epania sinyaporensis, but 

 a Bracon and a Reduviid bug. The mimicry is probably Miillerian in most, if not 

 all, of the species of this group. 



Another important set of Longicorns, species of Entelopes, Tropimetopa, 

 C/i?'eono7«a, and -4.sfrt;'/?.c.s were extremely perfect mimics of Phytophaga(G^ff/e;v/«'rf«). 

 In one large group both models and mimics were reddish brown, in another 

 iridescent blue-black, in a tliird anteriorly blue-black, posteriorly reddish brown. 

 Another species of Entelopes (E. ylauca) resembled a common Cocciuellid (Caria 

 dilatata), a Cassid also falling into the group. 



The Lycidce were models for Longicorns and other insects in Borneo no 

 less than in South Africa. Species belonging to the Longicorn genera Erythrus 



