Picture of a brown recluse spider. Note the violin pattern on the cephalothorax and light-colored hairless abdomen. Picture of a brown recluse spider. Picture of a brown recluse spider head close-up. Generalized symptoms of bites from black widow and brown recluse spiders may include: 1  fever,  nausea,
Standard Mileage Rate Law and Legal Definition. The standard mileage rate (SMR), also known as mileage per diem, is the amount per mile that the Internal Revenue Service (IRS) allows small businesses and self-employed persons to use to calculate their vehicle expenses for tax deduction purposes.
Each year the IRS announces a new standard business mileage rate that can be used by taxpayers to compute a deduction for the business use of a vehicle. This rate also can be used by employers to reimburse workers' substantiated business miles under an accountable expense reimbursement arrangement. The standard mileage rate is an important concept for church treasurers, since many churches reimburse staff members' business miles using this rate.