The members of `B_(n)H_(n+4)` series are less stable than `B_(n)H_(n+6)` series.

Explanation

To determine whether the statement "The members of BnHn+4 series are less stable than BnHn+6 series" is true or false, we can analyze the stability of these two series of boron hydrides (boranes).

### Step-by-Step Solution:

1. **Understanding Boranes**:
- Boranes are hydrides of boron, represented by the general formulas BnHn+4 and BnHn+6.
- They are known to be electron-deficient compounds.

2. **Identifying the Series**:
- The series BnHn+4 includes compounds like B2H6 (diborane), which is known to be relatively stable.
- The series BnHn+6 includes compounds that are generally more stable than those in the BnHn+4 series.

3. **Stability Comparison**:
- The BnHn+4 series is characterized by having fewer hydrogen atoms relative to boron atoms, leading to a higher degree of electron deficiency.
- The BnHn+6 series has more hydrogen atoms, which helps to stabilize the structure due to better electron pairing.

4. **Existence of Compounds**:
- Members of the BnHn+4 series are often less stable and may not exist theoretically or are less commonly encountered.
- In contrast, members of the BnHn+6 series, such as diborane (B2H6), are well-studied and have practical applications.

5. **Conclusion**:
- Based on the analysis, the statement that "the members of BnHn+4 series are less stable than BnHn+6 series" is **false**. The BnHn+6 series is more stable than the BnHn+4 series.

### Final Answer:
The statement is **false**.