Biomass of macroarthopods averaged 4.2 g/m2 in the top 20 cm of soil from annually burned tallgrass prairie vs. 2.7 g/m2 from unburned sites. Change in scarab beetle larvae and adult biomass (mostly Phyllophaga spp.) was responsible for this difference and averaged 3.4 g/m2 on burned sites vs. 1.7 g/m2 on unburned sites. Causal relationships between burning and increased scarab abundance remain speculative. The standing crop of belowground arthropod biomass of tallgrass prairie is 2- 10 times larger than that of aboveground arthropods