INTRODUCTORY NOTE 



THE small number of specimens in our collection, considering the 

 number of species represented, prevents any inference being drawn 

 as to the distribution of the Phytophagous Beetles of the Malay 

 Peninsula. As regards their bionomics also, what we can add amounts to little. 

 One point may be noted — the resemblance between mar?y of the species of 

 the peculiar Dipterous family Celyphidae and the small, globular, iridescent 

 blue or purple Phytophaga so abundant in Malaya, belonging to a great 

 number of species but closely similar to one another save in the eyes of 

 a specialist. These little beetles and flies have much in common as regards 

 movements and habits ; but the flies are by far the scarcer. Both shun a bright 

 light or great heat, retiring under the shelter of foliage at mid-day, but 

 emerging to run about on the surface of leaves whenever the air is cool after 

 rain and in the early morning and late afternoon ; both have the same rapid, 

 rather jerky gait; both take to flight with surprising ease, apparently without 

 muscular effort, on the slightest disturbance. The flies may readily be distin- 

 guished from the beetle, on examination, by their tongues, which are 

 constantly being applied, seemingly with a sucking action, to the surface of 

 the leaves ; but a casual glance rarely suffices to tell which is which. Some 

 Malayo-Siamese Celyphids, however, have not the deep hues and brilliant 

 iridescence of their more numerous congeners ; they, too, are like Phytophaga 

 in shape and movements, but seldom resemble any one species or genus in 

 detail. 



It is doubtful whether this is a case of true mimicry, not rather one of 

 adaptive resemblance. Between the Celyphidae and many of the Hemipterous 

 family Pentatomidae a similar, but not so close, a superficial likeness exists, and in 

 this instance, though the resemblance is less striking to the human eye, the 

 structural convergence is much greater, both fly and bug possessing a false 

 carapace beneath which the functional wings can be concealed and protected. 

 The carapace thus performs the same function as the elytra of a beetle. 

 In both elytra and carapace there is a common production of dark pigment 

 combined with peculiarities of form, which produce iridescence or metallic 

 lustre more or less conspicuously in different instances. 



NELSON ANNANDALE 



Indian Museum, Calcutta 

 April 12, 1905 



