Tree Cattle (Cerastipsocus venosus)

These delicate, ephemeral little black “flies”, about 6-8mm long, are actually bark lice — Cerastipsocus venosus — with the appallingly banal common name of tree cattle. (They actually share this common name with a number of other species of bark lice.) Both adults and nymphs of C. venosus form crazy-large groups (like herds of cattle,…