To further understand the parasitic mechanisms of W. magnifica, with reference to the functional distribution of ES proteins, relevant literature on myiasis-causing flies, and the parasitic characteristics of W. magnifica, we choose four likely parasitism-related gene families, including peptidase, cuticle protein, heat shock protein (hsp), and immune response genes, and investigated their expression patterns, especially the larvae collected from the host’s wounds. The gene discussed is HSP90B2P; the disease is myiasis.