Care to share the link?http://www.everlight.com/datasheets/PT333-3C_datasheet.pdf
A quick Google search reveals that "cockroach catcher" is in other Everlight datasheets.
Might be a spell checker mistake.
"Cockroach catcher" a spell checker mistake? Maybe in Chinese but certainly not in English. There aren't many (any?) words close to "cockroach" in spelling.
But if a phototransistor can catch cockroaches, I know a few family members that could use them..
I'm certainly wondering how the phototransistor is used in that application. If I figure it out I'll pass on the news.
Sidebar: I am very pleased with the phototransistor referenced above. It plus a 100 KΩ resistor is an excellent choice for detecting "dark".