"The First Brood" refers to the initial generation of cicadas that emerge after a long period of development underground. These insects typically spend several years, often 13 or 17, in their nymph stage before they surface, molt, and become adults. This emergence is synchronized, leading to large numbers of cicadas appearing at once. During this time, the adult cicadas mate, lay eggs, and then die shortly after. The eggs hatch into nymphs, which fall to the ground and burrow into the soil, starting the cycle anew. This phenomenon is particularly notable in periodical cicadas, which are known for their unique life cycles.