Abstract The stygnopsid harvestman Chinquipellobunus madlae (Goodnight and Goodnight 1967) is known from numerous caves in eleven counties in Texas and is a highly adapted troglobiont (Cokendolpher 2004). Adult and juvenile specimens were extracted in methanol, and the major volatile component of their chemical defense secretion was identified as 2-methyl-5-ethylphenol; a minor component was 2, 5-dimethylphenol. Methylethyl phenols and dimethyl phenols have also been identified in other grassatorid Opiliones, but this is the first report of defensive chemistry from a member of the family Stygnopsidae and from a North American troglobiont harvestman.