Allacma fusca is a widespread and common species found in a variety of moist habitats near to the ground surface. It is a large dark brown springtail reaching 3.5 mm in length (Fig. 1). The fourth antennal segment (ant4) is divided into 16 subsegments. Some setae on the third antennal segment (ant3) are longer than others (Fig. 2). The outer edge of the mucro is smooth and the inner edge is serrated (Figs. 3, 4). The female sub-anal appendages (SAA) are not branched at the tip (Fig. 5). The empodium on the foot is longer than the claw which is encased in a sheath (Fig. 6). A small post-antennal organ (PAO) is present (Fig. 7).

Back to main page

Fig. 1 (above): Allacma fusca of 3.5 mm in length from a garden in Reading.

Fig. 2 (above): Middle section of the antenna of Allacma fusca collected from Lynmouth, South Devon in July 1955 by D.J. Clark.

Fig. 3 (above): Furca of Allacma fusca collected Reading in July 1980 by  Peter Lawrence.

Fig. 4 (above): Mucro of the same specimen of Allacma fusca shown in Fig. 2.

Fig. 5 (above): Female Sub Anal Appendage (SAA) of the same specimen of Allacma fusca shown in Fig. 2.

Fig. 6 (above): Foot of the third leg of the same specimen of Allacma fusca shown in Fig. 2.

Fig. 7 (above): Eye patch (ocelli) and post-antennal organ (PAO) of the same specimen of Allacma fusca shown in Fig. 2.