The fingerprint-like structures on this female root knot nematode help scientists to identify it. (Image courtesy ARS Nematology Lab, D3603-1)
ARS nematologist David Chitwood (left) and microbiologist Zafar Handoo examine some of the nearly 50,000 slides and vials in the USDA Nematode Collection. (Stephen Ausmus, D3602-1)