About Promecognathus crassus LeConte, 1868
Promecognathus crassus is a species of ground beetle that belongs to the family Carabidae. This beetle is found along the Pacific coast of North America, ranging from British Columbia down to California. Like its close relative Promecognathus laevissimus, P. crassus uses its large jaws to feed on millipedes. This includes millipede species such as Xystocheir dissecta, which produce hydrogen cyanide and benzaldehyde. P. crassus has a high tolerance to these defensive toxins.
