Alfa is a typical "teenage" cat _ curious, mischievous and loving. She is the last of a litter of kittens that came to the SPCA shelter. Volunteers say whoever adopts her will be fortunate because the best was saved for last. Inquiries about adopting Alpha and other cats and dogs can be made at the Society for the Prevention of Cruelty to Animals of Hernando County, 9075 Grant St., west of Brooksville. The shelter is open from 11 a.m. to 3 p.m. every day. Adoption fees include rabies shot, heartworm testing, worming and spay/neuter. Fees for cats also include testing for feline leukemia and AIDS. The cost for dogs is $68; for cats, $58. Visit the web site at petshelter.org. For information, call 596-7000.