Notes on East African Aphids VI- Cereal and Crass Root-Feeding Species

Abstract

About 15 cereal and grass feeding aphids are known to occur in East Africa. Five of them live only at or below soil level and these are described here, together with a few other species that may have been overlooked in the past or be introduced in the future. There is little information about the economic importance of grass and cereal root aphids in the Old World, but in America several species are recognized as pests. The root aphids may be divided into two groups. The sub-family Eriosomatince contains white, very pale green, pale yellow or pink aphids, with short antennw, the last segment of which has only a short processus terminalis (Figs. A-N), whose adult apterx and immature stages of all forms have eyes of only three facets, whose siphunculi are small or absent and the winged forms of which have the media of the forewing unbranched. The second group comes in the sub-family Aphidince and resembles the ordinary" greenfly" in having longer antennw with a slender processus terminalis (Figs. PZ), siphunculi elongate, all stages of all forms with large compound eyes and the alatee have the media of the brewing once or twice forked. These aphids may be of various colours but are not white, very pale green or yellow or completely pink like the Eriosomatimr. Ancecia, a genus of the sub-family Thelaxince, contains wheat, barley and grass root-feeding aphids with black adult apterx and white larvw. The antennw and eyes are similar to those of the Eriosomatince, but the genus may be recognized by the presence of flat cone-like siphunculi and conspicuous lateral abdominal tubercles which are absent in grass root-feeding Eriosomatince, first tarsal segments with seven hairs and with 12 to 20 hairs on the second antennal segment. The media of the forewing of the alatx is once forked. Ancecia is not known from East Africa but is recorded from Egypt, Europe, Asia and North America.