Eight new species of Macrosiphum Passerini (Hemiptera: Aphididae) from western North America, with notes on four other poorly known species

Eight new species of Macrosiphum from western North America are described, with notes on biology and relationship to other Macrosiphum: Macrosiphum badium, n. sp., from Maianthemum spp. (Liliaceae), Macrosiphum claytoniae, n, sp., from Claytonia spp. (Portulacaceae), Macrosiphum holodisci, n. sp., from Holodiscus discolor (Rosaceae), Macrosiphum oregonense, n. sp., from Lysichitum americanum (Araceae), Macrosiphum vancouveriae, n. sp., from Vancouveria hexandra (Berberidaceae), Macrosiphum violae, n, sp., from Viola glabella (Violaceae), Macrosiphum willamettense, n. sp., from Spiraea douglasii (Rosaceae), and Macrosiphum wilsoni, n. sp., from Disporum spp. (Liliaceae). In addition, notes on biology and taxonomy are provided for four previously described, but poorly known, species of Macrosiphum: Macrosiphum insularis (Pergande) (= Macrosiphum yagasogae Hottes, new synonymy), which has been found on Streptopus amplexifolius (Liliaceae) in Oregon, Macrosiphum occidentalis, which feeds on Oemleria cerasiformis (Rosaceae), Macrosiphum tolmiea (Essig), which has been found on Mitella caulescens, Tellima grandiflora, and Tolmiea menziesii (Saxifragaceae) in Oregon, and Macrosiphum tuberculaceps (Essig), which feeds on Achlys triphylla (Berberidaceae). A key to the North American Macrosiphum species feeding on Liliaceae is also presented.