The morphology of the larval stages of one species (Arrenurus buccinator) is redescribed and two species (A. muelleri and A. stjoerdalensis) are described for the first time. The three species belong to the Megaluracarus subgenus. Particular attention is paid to the characters in common in the three species which they share with other Megaluracarus species and differences also from the species in the other subgenera. These are: shape of excretory pore plate, length of coxal plate median margins, the distances of C1-CpI and C4-CpIII and location of the IITi10 and IIITi10 setae. There are some characters which differ in the three species as well. These are: shape of dorsal plate, shape of excretory pore plate and presence or absence of secondary setae on the IFe3, IIFe3 and IIIFe3 setae.