Amphicercidus Oestlund 1923

Amphicercidus Oestlund, 1923 Amphicercidus Oestlund, 1923: 126. Type species. Aphis pulverulens Gillette, 1911 by original designation. Diagnosis. Body elliptical and heavily covered with white wax powder in life; body dorsum smooth, abdominal tergites often with large and round marginal or spinal tubercles; setae of body dorsum and appendages long and pointed; head with undeveloped diverging antennal tubercles; median frontal tubercle flat or slightly swollen; antennal segment III with 3–49 secondary rhinaria in apterae and 2–152 secondary rhinaria in alatae; the second hind tarsal segment at least 1.50 × of ultimate rostral segment; siphunculi as long stout cylinder, without flange, smooth or with fine transverse wrinkles; cauda broad, about as long as or slightly longer than its basal width. The genus resembles Macchiatiella Del Guercio, 1909 in antennal segment III with secondary rhinaria and broad cauda, but it can be distinguished by the following characteristics: (1) antennal tubercles undeveloped (in Macchiatiella: antennal tubercles well developed); (2) body dorsum without sclerotized markings (in Macchiatiella: body dorsum with sclerotized markings); (3) second hind tarsal segment at least 1.50 × of ultimate rostral segment (in Macchiatiella: second hind tarsal segment shorter than ultimate rostral segment); (4) siphunculi without flange (in Macchiatiella: siphunculi with flange). The genus also resembles Allocotaphis Börner, 1950 in having broad cauda, but it can be distinguished as follows: (1) abdominal tergites smooth, without sclerotized markings (in Allocotaphis: abdominal tergites often with sclerotized markings); (2) setae of body dorsum and appendages long and pointed (in Allocotaphis: setae of body dorsum and appendages short and pointed or capitate); (3) antennal segment III with numerous round secondary rhinaria in alatae (in Allocotaphis: antennal segment III with protuberant secondary rhinaria); (4) second hind tarsal segment at least 1.50 × of ultimate rostral segment (in Allocotaphis: second hind tarsal segment shorter than ultimate rostral segment); (5) siphunculi without flange (in Allocotaphis: siphunculi with developed flange). The genus also similar to Anuraphis Del Guercio, 1907 in having broad cauda, but it can be distinguished as follows: (1) most species feeding on Lonicera (Caprifoliaceae) (in Anuraphis: the species transfer between Prunus (Rosaceae) and Asteraceae or Apiaceae); (2) body dorsum without sclerotized markings (in Anuraphis: body dorsum with sclerotized markings) (3) siphunculi long stout cylinder, smooth or with fine transverse wrinkles, without flange (in Anuraphis: siphunculi short cylinder and tapering, with close-set rows of minute fine spinules, with distinct flange); (4) second hind tarsal segment at least 1.50 × of ultimate rostral segment (in Anuraphis: second hind tarsal segment shorter than ultimate rostral segment). Biology. Most species feed on the shoots and leaves of Lonicera (Caprifoliaceae), but Amphicercidus flocculosus (Gillette & Palmer, 1929) and Amphicercidus pulverulens (Gillette, 1911) feed on Symphoricarpus (Caprifoliaceae), and Amphicercidus laniger (Takahashi, 1927) feeds on the young stems of Stauntonia (Lardizabalaceae) (Blackman and Eastop 2024). Distribution. China, Japan, Korea, India, Central Asia, Russia, USA, Canada, Mexico (Blackman and Eastop 2024).