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Uroleucon cirsii · amarai

You may see eggs of some parasite on rightmost aphid.

  • Large Thistle Aphid
  • Agertidselbladlus

Uroleucon cirsii is found throughout Europe and has been introduced to North America. Large: 4 - 5 mm, found on Cirsium (usnis), especially Cirsium arvense (dirvinė usnis). It has characteristic two tone legs. Dark-tailed Thistle Aphid (Uroleucon aeneum) is similar and also uses Thistle as a host plant, but Uroleucon aeneum has an all black cauda (tail) whereas the cauda is dusky yellow in Uroleucon cirsii.

Uroleucon cirsii apterae are bronzy or reddish brown with pale legs that are darkened towards the apices of the segments. Abdominal hairs are placed on pigmented scleroites. Spinal scleroites are fused into larger sclerites, each normally with three hairs. Crescent shaped antesiphuncular sclerites are present (cf. Uroleucon aeneum and Uroleucon jaceicola which do not have antesiphuncular sclerites). The siphunculi are 0.25-0.34 times the body length, and 1.6-2.2 times the length of the cauda, with polygonal reticulation on less than the distal 0.25 of their length. The slightly dusky yellow cauda has 20-33 hairs (cf. Uroleucon aeneum which has a black cauda). The alate is bronzy or reddish brown much like the aptera with a pale cauda and pale legs that are darkened towards the apices of the segments. Oviparae and dark green males appear in late September to October, and eggs are laid on the undersides of the radical leaves.

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