6 A. WATSON 



some Papilionidae (e.g. Parides) are well documented (Brower, L. P., 1963; Brower, 

 J. V. Z., 1963; Brower, Brower & Collins, 1963; Turner, 1968). There are, in fact, 

 similar intra- and intergeneric associations in those Arctiidae studied by Blest; 

 the seemingly anomalous situation he found being the result of the taxonomic 

 disorder initiated by Hampson. In this paper the effects of Hampson's 'lumping' 

 are corrected, fairly typical Mullerian associations are revealed and it becomes 

 unnecessary to postulate explanations such as Tinbergen's (i960) theory of specific 

 search images (Blest, 1964). 



The aposematic coloration of Eupseudosoma-gronp Arctiidae is not invariably 

 exposed when the moths are at rest, in contrast to the blatantly advertised coloration 

 of some unpalatable butterflies. It seems a reasonable assumption that the almost 

 uniformly brown Himerarctia griseipennis Rothschild (p. 40) is a procryptic species 

 when at rest; but when the wings are unfolded the bright yellow (or orange) and 

 iridescent greenish blue aposematic coloration of the abdomen is exposed. Species 

 such as griseipennis have apparently evolved a dual defence system involving 

 cryptic coloration as the first line of defence against predators, supplemented by 

 distastefulness (advertised by abdominal coloration) when warning display behaviour 

 has been activated by predators. Blest (1964) has emphasized the fact that many 

 Arctiidae (as in other groups of unpalatable Lepidoptera) have a tough and resilient 

 cuticle which is able to withstand investigatory pecking by birds. 



Those Eupseudosoma-group species which have brightly coloured fore wings, as 

 weU as a conspicuous abdomen, potentially have two phases of warning colour 

 signals. Himerarctia laeta sp. n., for example, has bright orange forewings which 

 are as conspicuous at rest as in flight, while Viviennea moma Schaus and many 

 Ormetica Clemens species have black and yellow forewings (a combination of colours 

 generally considered to be aposematic (Frazer & Rothschild, i960)). All these 

 species have brilliantly coloured abdomens which are exhibited during warning 

 display (see figures in Blest, 1964). White and pale yellow species, which are 

 unlikely to prove to be cryptically coloured in their resting surroundings, may 

 also fall into this category. Blest (1964) demonstrated that two yellow species 

 of Selenarctia gen. n., one white species of Eupseudosoma and three mostly white 

 species of Idalus are unpalatable to Cebus monkeys. Each displays its orange 

 or red abdomen during warning display. In these species, the disadvantages of 

 being potentially less successful in concealment are apparently outweighed by the 

 advantages of being able to signal an instant visual aposematic message to a predator 

 possessing the necessary colour-vision. That attempts at diurnal concealment 

 are made by most warningly coloured night-flying Arctiinae, seems reasonably 

 certain from my observations in Venezuela and south-west United States, and those 

 of R. E. Dietz in Costa Rica and Venezuela, J. P. Donahue in Costa Rica, E. L. Todd 

 in Jamaica, and F. Fernandez Yepez in Venezuela (1973, personal communications), 

 thus tending to qualify the generalization (Remington & Remington, 1957; Roths- 

 child, 1972) that noxious, warningly coloured moths choose exposed positions 

 when at rest during the day. 



The possibility that white Idalus and Eupseudosoma species may prove to have at 

 least a partly crepuscular flight is worth investigating. Hyphantria cunea Drury 



