ARCTIIDAE AND CTENUCHIDAE FORMERLY IN AUTOMOLIS 7 



(the Fall Web-worm) has been shown to start flying before sunset in Japan (Hikada, 

 1972) at which time its conspicuous whiteness could be aposematic and provide a 

 selectively advantageous warning signal to crepuscular avian predators such as 

 night-hawks which locate their prey visually. 



The genera Viviennea gen. n., Ordishia gen. n., Ormetica Clemens and Idahts 

 Walker provide some of the best examples of Mullerian partnerships. Blest (1964) 

 has shown that some species of each of these genera are unpalatable to caged verte- 

 brates and produce the same type of warning display. The close similarity in 

 coloration and pattern between the groups of species in Ormetica, for example, 

 strongly suggests that these are Mullerian complexes. There may be, however, 

 limited Batesian mimicry within these groups - the presence of a moderately 

 palatable species in a Mullerian complex will tend to induce the evolution of a new 

 colour-pattern by a highly unpalatable member of the complex and lead to the 

 formation of a new complex of species (Pough et al., 1973) and may explain the 

 presence of several differently patterned groups of species in Ormetica. Each 

 of the species-groups in Ormetica has one especially constant character: the brilliantly 

 iridescent, greenish blue coloration of the posterior segments of the abdomen, a 

 character shared by all the species of Viviennea and Himerarctia gen. n. There 

 are close intergeneric similarities in the forewing coloration between the Ormetica- 

 group bonora Schaus, ochreomarginata Joicey & Talbot, luteola Rothschild, codasi 

 Jorgensen, postradiata Schaus and xanthia Hampson, and the Viviennea species 

 salma Druce and superba Druce. All of these are bright yellow species, with iridescent 

 greenish blue posterior abdominal segments, for which it is tempting to postulate 

 Mullerian affinities. Another example of probable Mullerian convergence is that 

 between the monotypic Etipiesia Fclder and the group of Ormetica species including 

 its type-species sphingiformis Clemens in which the forewing bears a conspicuous, 

 longitudinal, yellow stripe. 



The species Scaptius obscurata Schaus is possibly palatable to vertebrate predators 

 (Blest, 1964) and yet it exhibits the same type of display found in the aposematic 

 Viviennea, Ormetica, Ordishia, Selenarctia and others. The forewings of obscurata 

 have a broken pattern of yellow and brown so that the moth is probably effectively 

 procryptic when at rest; but in the warning display posture the bright orange-red 

 abdomen is displayed in the same way that the red abdomen of Idahis species is 

 exhibited. This seems to be a Batesian situation in which the warning display 

 behaviour and the abdominal warning coloration of the unpalatable Mullerian 

 models are copied. There remains the possibility, however, that obscurata is 

 unpalatable to certain diurnal predators and is both a Batesian and a Mullerian 

 mimic, as most Arctiidae and Ctenuchidae do seem to be distasteful, if not actively 

 harmful to a variety of predators (Beebe & Kennedy, 1957; Blest, 1964; Rothschild, 

 i960; 1 961; Aplin & Rothschild, 1971 : 590). 



WARNING SOUNDS 



By means of their tymbal organs (the modified metepisterna), species of the 

 Eupseudosoma-gvonp, as many other species of Arctiidae and Ctenuchidae, produce a 



