Shield Bug nymphs

Shield Bug nymphs

Observation - Shield Bug nymphs. Description: The lower one was seen on a garden Euphorbia on 30th June 2010, the upper one on bamboo on 22nd September 2011 in the same garden. In each case there were several on the same plant. They were seen 3 months apart, though different year, so are they differe

The lower one was seen on a garden Euphorbia on 30th June 2010, the upper one on bamboo on 22nd September 2011 in the same garden. In each case there were several on the same plant. They were seen 3 months apart, though different year, so are they different species or just different stages of development?