 Species of this genus are also characterised by their elongated mandibles and large compound eyes that provide excellent vision . They vary in colour and size , ranging from 8 to 40 millimetres ( 0 @.@ 31 to 1 @.@ 57 in ) . Although workers and queens are hard to distinguish from each other due to their similar appearance , males are identifiable by their perceptibly smaller mandibles . Almost all Myrmecia species are monomorphic , with little variation among workers of a given species . Some queens are ergatoid and have no wings , while others have either stubby or completely developed wings . Nests are mostly found in soil , but they can be found in rotten wood and under rocks . One species does not nest in the ground at all ; its colonies can only be found in trees . 
