We carried out time-resolved V -band photometry of DM Lyr during long outbursts in 1996 July and in 1996 February-March at Ouda Station , Kyoto University and at Osaka Kyoiku University .
Since superhumps were clearly detected in the light curves , DM Lyr was first identified with an SU UMa-type dwarf nova .
The superhump period is 0.0673 ( 2 ) d , and the superhump excess is 2.8 ( 3 ) % .
The duration of the superoutburst , the outburst amplitude , the decline rate in the plateau phase , and the superhump excess were typical values for a usual SU UMa star .
According to visual and CCD observations reported to VSNET , this star has experienced a dramatic change of the outburst pattern from a superoutburst phase to a normal outburst phase .
There may exist mechanisms to decrease the number of the normal outburst between two successive superoutbursts and to elongate the recurrence cycle of the superoutburst .