Hemiargus ceraunus (ceraunus blue) and Leptotes marina (marine blue) feed on many legumes in nature.  If you obtain eggs from a female, one effective way to rear these is to feed them on snow peas.  Separate larvae to one per solo cup.  Place a portion of a snow pea pod into solo cup with larva.  Remove frass once a day when larva is small; switching to twice a day when larva is third or fourth instar.  Replace peas either morning and evening or once a day.