Lower field: in termini; see costal field.
Lower fronto-orbital bristles: in Diptera: are on the lower part of front, above the antennae, along the orbit.
Lower margin: of tegmina (Thomas), is the costal or anterior margin of other authors.
Lower radial vein: in Lepidoptera (Holland) media 2 (Comst.).
Lower sector of triangle: in Odonata - = cubitus 2 (Comst.).
Lower Sonoran faunal area: comprises the most arid deserts of North America, beginning west of lat. 98 degrees in Texas: sends narrow arms into southern New Mexico, is interrupted by the Continental Divide; covers a large part of w. and s. Ariz., s. w. Nev., s. w. Calif., a portion of central Calif., and most of Lower Calif. These areas are irregular and incapable of brief definition.
Lubricate -ous: covered with a slippery mucus.
Lucid: shining; applied to luminous insects.
Luciferase: a substance in the nature of an enzyme, existing in the luminous organs of light-giving beetles.
Luciferine: a substance in the blood of luminous beetles which, when brought into contact with luciferase, produces light.