Moved from Sminthurinus niger.

Hopefully I'm not missing something here... not sure why these weren't moved sooner. If I made an error, just let me know and I'll put things back the way they were.

New species for the nearctics!
In habitus shots we can use this key to distinguish niger from lawrencei :
white eyebrows small and short, inbetween distance more than 2 times the width of an eyebrow : lawrencei
white eyebrows large and long, inbetween distance less than 2 times the width of an eyebrow

Moved from Katiannidae.

Moved from Springtails and allies.

Quite interesting. At first it reminds me at the European Sminthurinus niger. Christiansen & Bellinger (1998) consider all nearctic records of S. niger as dark coulour forms of S. quadrimaculatus.
To verify the genus, we need a true anal shot: the anus in the center of the image, above the anus the dorsal anal valve, below the 2 ventral anal valves (left and right one). On the dorsal anal valve, in opposite position of the median suture between the 2 ventral anal valves, thus median, there is a distinct macroseta. In Sminthurinus this macroseta is bifid (bifurcate). In Katianna s.l. (Polykatianna, Neokatianna, Katiannina) it is not bifid. This is the 1st thing to check.