Disclosed is a novel .delta.-endotoxin, designated CryET29, that exhibits insecticidal activity against siphonapteran insects, including larvae of the cat flea (Ctenocephalides felis), as well as against coleopteran insects, including the southern corn rootworm (Diabrotica undecimpunctata), western corn rootworm (D. virgifera), Colorado potato beetle (Leptinotarsa decemlineata), Japanese beetle (Popillia japonica), and red flour beetle (Tribolium castaneum). Also disclosed are nucleic acid segments encoding CryET29, recombinant vectors, host cells, and transgenic plants comprising a cryET29 DNA segment. Methods for making and using the disclosed protein and nucleic acid segments are disclosed as well as assays and diagnostic kits for detecting cryET29 and CryET29 sequences in vivo and in vitro.