Apterygogenea: those insects that are wingless in all stages and presumed to be descended from ancestors which never were winged: see pterygogenea. Apterygota: = apterygogenea; see pterygote. Aquamarine -us: sea green: pale green with predominant blue and a little gray [nile green]. Aquatic: living wholly in water. Aquatilia: cryptocerous Hemiptera of truly aquatic habit. Arachnoideous: resembling or similar to a cobweb. Araneiform: spider-like in appearance. Arboreal: living in, on, or among trees. Arborescent: branching like the twigs of a tree. Archaic: ancient; no longer dominant; of the olden time. Archiptera: those Neuroptera with incomplete metamorphosis = Pseudo-neuroptera. Arctic Zone: is that part of the boreal region above the limit of tree growth in the U. S. is restricted to the area above timber line on the summits of high mountains: = alpine. Arcuate: curved like a bow: = arcuate. Arcuato-emarginate: with a bow-like or curved excision. Arculus: Odonata; a small cross vein between radius and cubitus near the base, leaving an elongate triangle between them: Trichoptera; a point, often hyaline, on the forewing where the cubitus (or post cubitus) runs into the margin: in Homoptera; a cross-veinlet nearly reaching posterior margin at same point as in Trichoptera: in other orders applied to a cross-vein in similar position, apparently giving rise to the median. Arcus: a bow; part of a circle; but less than one half. Area mediastinal, scapularis and ulnaris: the areas in front of the mediastinal, the scapular, and the ulnar veins in Orthoptera. Areae or Areolae: wing cells or spaces between veins. Arenicolous: applied to species frequenting sandy areas. Arenose: a surface that is sandy or gritty. Areola: a small cell on the wings of certain Hemiptera: see also areae Hymenoptera; the central of three median areas on the metanotum: = 2d median area; upper median area. Areolate: with small defined areas, like a network. Areole: Lepidoptera; see accessory cell, cell and cellule. Areolet: one of the small spaces between veins of net-veined insects. Argentate: shining, silvery white. Argenteous: silvery. Argillaceous: of the texture, appearance or color of clay. Arid: Applied to regions in which the normal rainfall is insufficient to produce ordinary farm crops without irrigation, and in which desert conditions prevail: see humid. Arid transition area: comprises the western part of the Dakotas, northern Montana east of the Rockies, southern Assiniboia, small areas in southern Manitoba and Alberta, the higher parts of the Great Basin and the plateau region generally, the eastern base of Cascade Sierras and local areas in Oregon and California. Arista: a specialized bristle or process on antennae of certain Diptera. Aristate: Diptera; that type of antennae that bears an arista: = athericerous. Aristiform: of the form or appearance of an arista.