The experiment is such: Researcher uses foam rubber or plastic from the female alar collect secretion, dissolve is in at the inunction after alcohol the labrum of a few females.

研究人员用海绵从性腋下收集分泌物，精后擦在性的上唇。

The mandibles are usually lost, the labrum is reduced to a narrow transverse sclerite, and the labium is a small flap ( though its palps retain quite large).

上颚消失，上唇退化为条窄横片，下唇退化为小片（下唇须发达）。