Type I simple setae are smooth with a pore on the tip.They usually appear in groups with type II or denticulated setae and they are shorter than the type II and the denticulated setae.

• I型简单刚毛通体光滑，顶端逐渐变细，具一顶孔，常伴生II型简单刚毛和有齿刚毛，但长度比后两种的短；