To obtain more data on the system of levels in even-even nuclei, a number of such nuclei (

150 \leq A \leq 184

) were studied with electron-capturing sources in permanent magnet spectrogaphs. Some measurements were made with scintillation counters. Data confirming recently reported results on the decay of

{Tb}^{152}

{Tb}^{156}

, and

{Ho}^{162}

have been obtained. It was found that

{Eu}^{150}

has two isomeric states (

T_{\frac{1}{2}} = 14

hr and > 5 yr). Levels at 740.7 (0+) and 773.3 (4+) kev in

{Sm}^{150}

are proposed. A study of the two isomeric activities of

{Tb}^{154}

indicated the existence of levels in

{Gd}^{154}

which may be described as a gamma-vibrational band (at 997.3 kev) and a beta-vibrational band (at 680.6 kev). The new data for

{Tm}^{166}

(7.7 hr) are consistent with levels in

{Er}^{166}

at 2137.3 and 2164.6 kev, both of which are probably 3 states and which exhibit considerably different branching ratios of the de-exciting transitions. The decay of

{Lu}^{172}

appears to populate a large number of even-parity levels in

{Yb}^{172}

which may be arranged in rotational bands corresponding to primary or base states at 1174.0 kev (

I = 3 +

), 1467.5 kev (

I = 2 +

), 1664.3 kev (

I = 3 +

), 1702.1 kev (

I = 3 +

), 2075.0 kev (

I = 4 +

), and 2287.3 kev (

I = 4 +

). The very complex decay of the two isomers of

{Re}^{182}

excite many odd-parity levels which may be arranged in seven or more bands. In addition, even-parity beta- and gamma-vibrational bands may be populated. Electron-capture decay of

{Re}^{184}

populates a gamma-vibrational band in

W^{184}

of spins 2, 3, and 4. Data relevant to the rotational energy parameters and ratios of gamma-ray transition probabilities from the various states are presented. As a corollary, data on the decay of

{Eu}^{149}

are presented since this activity was present in some of our composite sources.

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