Numbers
Nearctica lists 9 species north of Mexico.
Identification
Using Gordon's ref.
(1), here's a simplified ID tree based on distribution and external characteristics:
1) C. stigma - entire US east of Siera Nevada mtn., Canada east of Rockies. Elytra spots appear to be much larger in southern range. Venter (around legs) mostly black, only abdomen red or yellow.
Exceptions within C. stigma's range:
2) C. cacti - Southern Arizona, CA, TX, and FL - Large elytra spots as with southern C. stigma. Venter mostly red or yellow. Only prosternum black.
3) C. tumidus - mid Atlantic states - venter mostly red or yellow. Only prosternum black.
4) C. hexacyclus - Alberta, eastern slope of Rockies - inseparable from C. stigma
5) C. kuwanae - Introduced throughout much of US from Japan/Korea, then known as C. similis var. japonicus. Similar to C. stigma and orbus except spots on elytra are located at middle or slightly behind middle, and are more rectangular, vice round. Lateral margin of elytra strongly flared. See
here.
West coast Chilocorus:
6) C. orbus - probably west coast US, CA to Wash., not reaching Canada. Venter like C. stigma
7) C. fraternus - probably same distro as C. orbus. Externally inseparable from C. orbus.
8) C. tricyclus - probably British Columbia. Externally inseparable from C. orbus.
9) C. bipustulatus - San Joaquin Valley CA. Introduced from Europe. Dorsal pattern unlike any other Chilocorus, with irregular transverse band of 3 partically connected spots.
See Also
Hyperaspis sp. - Several Hyperaspis can have the "black with red 2 spots", including
.
Chilocorus normally has a bit of flatened margin around the lateral elytra edge, specially toward the shoulders. They also can appear slighly pointed posterially, and/or appear to be more of an A-frame, than evenly convex as Hyperaspis does. Some Hyperaspis make it easy, with white markings on the head or front and lateral margins of the pronotum. But the all-black ones are more challenging.
Also,
Calvia quatuordecimguttata (black / 2-spotted color form) - again the lateral edge shape shows that this is not
Chilocorus. Spots are also usually a little flattened apically, with a bit of a jagged edge and sometimes a little pink.
,
,
Another "two-spotted" is the dark form of Ashy-Gray Ladybird Beetle - Olla v-nigrum. These are easily distingished by the white pronotum and the spots more of a rounded right triangle with the hypotenuse sloped toward the suture apex.
