pygidium

Pygidial axis up to 90% of pygidial length, very gently constrained posteriorly, with eight axial rings plus a very short terminal piece.

In general, these can be broadly grouped into four categories: cerebral, segmental, pygidial, and radiolar.

melanocephalum workers effectively utilize their pygidial gland secretions as an alarm-defense system during aggressive encounters with other invaders (Tomalski et al., 1987).

Harper, "An Early Cambrian Stem Polychaete with Pygidial Cirri," Biology Letters 7 (2011): 929-32.

Pygidial shield present, its margin undulate and bearing one pair of smooth and needle-like setae (ca 50-60 [micro]m), surface of this plate covered by oval pits.

Hosts for these species are unknown, but each species had a well-defined pygidial plate.

"We found that the major constituent in the pygidial gland defensive fluid of the ground beetle Ardistomis schaumii is (r)-(+)-limonene, whereas that of closely related species Semiardistomis puncticollis is (S)-(-)-limonene," he said.

Pygidial plate broad and subtruncate, its lateral carina not rounded (Tsuneki, 1983a: 73-77).

1a); base of metepisternum, apex of metacoxa and lateral areas of ventral segments 2 to 5 with dense white hairs; legs with sparse white hairs; undersurfaces with moderately dense white to golden pubescence; pygidial pubescence varying from uniform, moderately dense white hairs to white or brown hairs with a dense median stripe of white hairs.

Dorsal and pygidial dressing velvety or setiferous.

These arachnids are well known for their ability to spray defensive, vinegar-like secretions from their pygidial glands (Schmidt et al.

The Bohemian Actinopeltis Hawle & Corda, 1847 has rather short pygidial spines similar to those of Reraspis, but the number of thoracic segments is smaller whereas the number of pygidial segments is higher.