This paper proposes the first attempt for semi-automatic screening and identification of red imported fire ants (Solenopsis invicta) in Australia. As an exotic ant species to Australia, fire ants were imported from South America in 2001 and have since been regarded as dangerous pests that could severely damage the environment and many industries. We followed two of the three major identification keys defined by entomologists and proposed: 1) A fusion of two different image features (i.e., the perpendicular median intensity and the perpendicular width) for antenna segment detection; and 2) A weighted histogramming of micropattern features for petiole classification. Our experimental results show that automatic on-site fire ant screening is feasible and the proposed weighted histogramming of micropattern features performs better than the original micropattern representation.