I'm not completely sure about the ID I've suggested as I don't know how to differentiate between the potential IDs I've found.
Skimming through M. Gleeson's 'Miniature Lives', I've noted the following as similar in appearance:
Solenopsis mealybugs (Phenacoccus solenopsis) p.153
Larvae of a mealybug ladybird (Cryptolaemus montrouzieri) p.192
CNM has some under Coccinellidae sp (family), and some specifically under C. montrouzieri. There may be more that I haven't come across.