Bombycinous: a very pale yellow like fresh spun silk.
Boreal: from or belonging to the north: is that faunal region that extends from the polar sea southward to near the northern boundary of the United States and farther south occupies a narrow strip along the Pacific Coast and the higher parts of the Sierra-Cascade, Rocky and Alleghany Mountain ranges; divided into Arctic, Hudsonian and Canadian: see austral and tropical.
Borer: applied to an insect or larva that burrows or makes channels in woody or other vegetable tissue.
Botryoidal: clustered like a bunch of grapes.
Bouclier: the pronotum, q.v.
Bouton: a button; the terminal lappet-like process at the tip of the ligula in bees: = spoon.
Brachelytra: with abbreviated wing covers or elytra.
Brachia: the arms: has been applied to raptorial fore-legs.
Brachial: relating to an arm; arm-like.
Brachial cells: Hymenoptera; 1st (Nort.), = costal and subcostal (Comst.) 2d (Nort.), = medial (Comst.); 3d (Nort.), = cubital (Comst.); 4th (Nort.), = 2d anal (Comst.).