Disclosed is a solid form of 4- 5- 3-chloro-5-(trifluoromethyl)phenyl -4,5-dihydro-5- (trifluoromethyl)-3-isoxazolyl - iV- 2-oxo-2- (2,2,2-trifluoroethyl)amino ethyl - l - naphthalenecarboxamide (Compound 1). Also disclosed are composi tions containing a solid form of Compound 1 and methods for controlling an invertebrate pest comprising contacting the inverte brate pest or its environment with a biologically effective amount of a solid form of Compound 1 or a composition containing a solid form of Compound 1.
