Identification of Capillaria spp. of nematode under the microscope at 10X objective (a) Capillaria spp. Female: Female Capillaria spp. are larger and have a thicker, more cylindrical body. Their tail is typically more rounded (b, c) Capillaria spp. Male: Male Capillaria spp. are smaller in size than females and have a more cylindrical and tapered body.