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 ba dium, n. sp., from Maianthemum spp. (Liliaceae), Macrosiphum claytoniae, n, sp., from Claytonia spp. (Portulacaceae), Macrosiphum holodisci, n. sp., f rom Holodiscus discolor (Rosaceae), Macrosiphum oregonense, n. sp., from Ly sichitum americanum (Araceae), Macrosiphum vancouveriae, n. sp., from Vanco uveria hexandra (Berberidaceae), Macrosiphum violae, n, sp., from Viola gla bella (Violaceae), Macrosiphum willamettense, n. sp., from Spiraea douglasi i (Rosaceae), and Macrosiphum wilsoni, n. sp., from Disporum spp. (Liliacea e). In addition, notes on biology and taxonomy are provided for four previo usly described, but poorly known, species of Macrosiphum: Macrosiphum insul aris (Pergande) (= Macrosiphum yagasogae Hottes, new synonymy), which has b een found on Streptopus amplexifolius (Liliaceae) in Oregon, Macrosiphum oc cidentalis, which feeds on Oemleria cerasiformis (Rosaceae), Macrosiphum to lmiea (Essig), which has been found on Mitella caulescens, Tellima grandifl ora, and Tolmiea menziesii (Saxifragaceae) in Oregon, and Macrosiphum tuber culaceps (Essig), which feeds on Achlys triphylla (Berberidaceae). A key to the North American Macrosiphum species feeding on Liliaceae is also presen ted.