52 
Psyche 
[Vol. 92 
large amphipods in the areas where M. marinum was common. All 
except barnacles seem likely as potential food for the beetles. Beetles 
(both adults and larvae) that I kept in culture fed avidly on freshly- 
killed adult Drosophila spp., and were apparently still healthy after 
up to three and one-half months of such a diet. One third-instar 
larva finished its larval development feeding on these flies and 
pupated successfully. Clearly Micralymma marinum are predators, 
but not obligate feeders on any element of their natural habitat; 
their usual natural food remains uncertain. 
King et al. (1979) suggested on the basis of collecting in southern 
Wales (at ca. 51°30'N) that M. marinum overwinter as eggs or as 
adults, hidden deep in rock crevices. Steel (1970) suggested on the 
basis of his collecting in southwestern England (at ca. 50°43'N) and 
in Scotland (at ca. 57°00'N) that adults overwinter and then lay eggs 
in May and June. One of the third-instar larvae I collected in Maine 
(at ca. 43°03'N) in late May pupated on 2 July and when preserved 
on 15 July appeared to be only a few days from adult eclosion. It 
appears from the last that in Maine some of the beetles may over- 
winter as larvae, or that the life cycle may be longer than one year. 
Steel (1970) found that most British Omaliinae overwinter as larvae 
(Thayer 1985 found the same for the North American species 
Brathinus nitidus LeConte and Lesteva pallipes LeConte), but M. 
marinum certainly occurs in a different habitat from most Omalii- 
nae and is undoubtedly subjected to different selective pressures. It 
is possible that the life cycle varies somewhat in different parts of the 
species’ range. 
With two exceptions, the morphological features discussed by 
King et al. ( 1 979) and Elliott et al. ( 1 983) in relation to the habitat of 
Micralymma marinum are all normal features of most or all Oma- 
liinae. The aptery of M. marinum is unusual, though certainly not 
unique, within the subfamily. Its connection with the habits of the 
species is open to question, however, since the other species in the 
genus ( M . brevilingue Schi^dte, M. caucasicum (Melichar)) are also 
apterous (Steel 1958, 1962) and M. marinum is the only one that is 
stricly marine intertidal (Steel 1962). Of perhaps more interest is the 
modification of the tarsal setae mentioned by both King et al. (loc. 
cit.) and Elliott et al. (loc. cit.). Micralymma marinum has, as they 
pointed out, flattened and widened ventral tarsal setae on the first 
four segments of all tarsi in both sexes. They are slightly more 
