Z. n. haldemani

Z. n. haldemani Horn, 1870, common names Haldeman's ironclad beetle^[8] or Texas ironclad Beetle,^[7] is sometimes treated as a separate species.^[2][9] It can grow between 1.5 and 2 centimetres in length. The body is a blotchy black-and-white pattern, and the legs are fully black.^[10][11] The subspecies name, haldemani, references the Haldeman brothers (Samuel Haldeman and Horace Haldeman), the former a naturalist and philologist, the latter a soldier and one of the first people to concentrate on insect collection in Texas.^{[12][13][7][9]}

They are thought to feed on lichen and dead plant material.^[7][11] Females have been observed laying eggs on American elms, and larvae and pupae have been found in pecan wood,^[11][9] which "apparently serves as the developmental site for this species".^[11] They are found in East and Central Texas.^[14][9]

Z. n. nodulosus

Z. n. nodulosus can grow between 1.4 and 2.8 centimetres in length, and 0.5 to 1.1 cm in width.^[15]

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  Z. n. haldemani
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  Z. n. nodulosus