To solve the problem of comparing the fractions \(-\frac{1}{3}\) and \(-\frac{5}{8}\), we need to convert them to a common denominator and then compare the numerators. Alternatively, we can convert them to decimal form and compare the decimal values.
Step 1: Define the Fractions
We have two fractions to compare:
\[
\text{fraction1} = -\frac{1}{3} \quad \text{and} \quad \text{fraction2} = -\frac{5}{8}
\]
Step 2: Convert to a Common Denominator
To compare these fractions, we can convert them to a common denominator. The least common multiple of the denominators \(3\) and \(8\) is \(24\). Thus, we convert each fraction:
\[
-\frac{1}{3} = -\frac{8}{24} \quad \text{and} \quad -\frac{5}{8} = -\frac{15}{24}
\]
Step 3: Compare the Numerators
Now we compare the numerators of the converted fractions:
\[
-\frac{8}{24} \quad \text{and} \quad -\frac{15}{24}
\]
Since \(-8 > -15\), we conclude that:
\[
-\frac{1}{3} > -\frac{5}{8}
\]
Final Answer
The comparison shows that \(-\frac{1}{3}\) is greater than \(-\frac{5}{8}\). Thus, the final answer is:
\[
\boxed{-\frac{1}{3} > -\frac{5}{8}}
\]