Abstract
Two new aphid species of the nominotypical subgenus of the genus Macrosiphoniella (Aphidinae) are described from Kazakhstan. Both species inhabits yarrow (Achillea millefolium L.). Macrosiphoniella kazakhstanica sp. n. most similar to M. silvestrii Roberti, 1954 but differs latter in the number of secondary rhinaria in apterous and alate viviparous females (5–10 and 24–26 vs 14–25 and 48–68), proportion of the processus terminalis to the base of the VI antennal segment (3.7–4.9 vs 2.8–3.6), proportion of antennal segment III to processus terminalis (0.82–0.98 vs 1.11–1.36), as well as the absence of dorsal sclerites at base of setae and color of all tibiae (brown in M. silvestrii and pale in the middle in new species). Macrosiphoniella sarmatica sp. n. is similar to M. terraealbae Kadyrbekov, 2000 but differs from latter in the ratios of the length of the processus terminalis to the length of the base of the 7th antennal segment (3.15–3.75 vs 2.7–3.1), length of the frontal setae to diameter of third antennal segment (1.6–1.7 vs 2.2–2.6), the number of accessory setae on the ultimate rostral segment (6 vs 7–8) and the number of setae on the cauda (10–13 vs 12–19).