Bed feeling a little crowded? Maybe you have company. The Cimex lectularius, better known and despised as the common bedbug, is snuggling into households across Southern California, giving people the heebie- jeebies. The blood-sucking, heat-seeking, pint-size parasites aren't believed by the experts to transmit disease, but they do have a way of cranking up stress levels. "It was just horrendous," said a West Hollywood middle-school teacher, who, like others who have been horrified to have lived with the uninvited guests, asked that she not be identified. "Think of how you wouldn't sleep at night if you had roaches, and this...