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n. pl. py·gid·i·a (-ē-ə)
The posterior body region or segment of certain invertebrates.

[New Latin, from Greek pugidion, diminutive of pugē, buttocks.]

py·gid′i·al (-ē-əl) adj.


(paɪˈdʒɪdɪəm; -ˈɡɪd-)
n, pl -ia (-ɪə)
(Zoology) the terminal segment, division, or other structure in certain annelids, arthropods, and other invertebrates
[C19: from New Latin, from Greek pugē rump]
pyˈgidial adj


(paɪˈdʒɪd i əm)

n., pl. -gid•i•a (-ˈdʒɪd i ə)
any of various structures or regions at the caudal end of the body in certain invertebrates.
[1840–50; < Greek pȳg(ḗ) rump + -idium]
py•gid′i•al, adj.
References in periodicals archive ?
The structures such as genitalia, antenna, abdominal segments IX-X, and pygidium were placed on glycerin mounts.
The shell-boring polychaete species were identified on the basis of fifth setiger chaetae, prostomium and pygidium morphology, and branchiae distribution.
Twig-nest parasitoids often have a smooth, undefined pygidium (Pitts and Manley, 2004; Pitts et al.
5); (v) trochanter IV unmodified; (vi) basal segment of pygidium unnotched on either dorsal or ventral posterior borders; (vii) fixed process of the male copulatory apparatus with an anteroventral ledge.
Also, a fragmentary pygidium attributed to the index species of the succeeding Megistaspis (Ekeraspis) armata Biozone (Balashova 1966, p.
7 mm long) and its pygidium is more highly polished with shagreening limited to its edges, instead of the entire surface.