Sminthurinusspecies are very variable in colour pattern and it is essential to examine the presence or absence of ventral subapical setae on the dens in order to make a correct identification. The'concolor-group' has TWO ventral subapical setae on the dens. Sminthurus concolor is black-violet in colour and is found out of doors. Sminthurinus trinotatusis also found out of doors and is predominantly black with a prominent white spot on either side of the abdomen. Two other species have been recorded from glasshouses, or flower pots inside buildings. These are Sminthurinus domesticus (bluish-black all over, sometimes with a yellow median band) and Sminthurinus igniceps(body bluish-black, head white or pale yellow). However, the ease with which springtails can be imported on exotic plants means that the exact origin and identity of these specimens remains uncertain.
There are a few scattered records in the literature for Sminthurus igniceps, all from glasshouses or other locations protected from frost. It reaches 0.7 mm in length and has a bluish-black body and a white or pale yellow head. The fourth antennal segment (ant4) is NOT subdivided. Both edges of the mucro are serrated. In females, the long setae surrounding the anus are expanded at the base and the sub-anal appendages (SAA) are feathery at the tips. The empodium of the second and third legs (leg2 and leg3) is slightly shorter than the claw, but is longer than the claw on leg1. The tenaculum (i.e. the 'catch' for the furca) has two setae. Apparently, Sminthurinus trinotatus is the only member of the 'concolor-group' with only one seta on the tenaculum.
The only specimen of Sminthurinus 'igniceps' in the NHML slide collection was taken in the Orchid House of Cambridge Botanic Gardens in February 1925 by C.H. Jackson. However, ventral subapical setae are absent from the dens and it cannot be 'igniceps' as defined by Bretfeld (1999). It could be an undescribed species. It would be interesting to see whether this taxon still survives in the Orchid House of Cambridge Botanic Gardens.