Aphis elena Lagos-Kutz and Voegtlin 2017, sp. nov.

Aphis elena Lagos-Kutz and Voegtlin sp. nov.

Diagnosis. Apterous viviparae similar to A. gossypii. Distinguished by the ratio of the length of siphunculus to the length of the cauda (SIPH/CA), 1–1.6 for A. elena and 1.3–2.5 for A. gossypii. Alate viviparae with few secondary sensoria in straight line restricted to antennal segments III (5–6) and IV (1–2). Distance from the base of antennal segment III to the first secondary sensorium (DBIII) 0.07–0.09. Forewing with median vein once-forked. Dark hind coxa. Cauda paler than siphunculus, with 6–7 setae. Ratio SIPH/CA=1–1.3. Marginal sclerites dusky.

Description. Apterous viviparae (n=22) (Table 1 and Figures 1–8). Color in life (Figure 18): Head, thorax and abdomen dark green, covered with white wax. Color of cleared specimens: Head: dark. Six antennal segments, rarely five (not included in morphometry): first, second, fifth and base of last antennal segment dusky; the remainder pale or slightly dusky. Ultimate rostral segment (URS) reaches the hind coxae. Thorax: Coxae dusky. Trochanters paler than coxae. Femora slightly dusky on distal half, basal tips pale. Tibiae pale, darkening near distal tip. Tarsi dusky. Abdomen: Cauda dusky and slightly spoon-shaped with inward curled setae. Siphunculi dark, imbricated with flange. Pre and post-siphuncular sclerite absent. Marginal sclerites pale. Marginal tubercles on abdominal II, III, and IV absent. Dorsum of abdomen without sclerites, cuticle with reticulation. Sub-genital plate dusky and complete.

Alate viviparae (n=6) (Table 1 and Figures 9–17). Color of cleared specimens: Head: Head and thorax dark. First and second antennal segments darker than other segments. Secondary sensoria restricted to antennal segments III and IV, arranged in a single row. URS reaches hind coxae, with 2 accessory setae. Thorax: Fore and middle femora dusky throughout. Hind femora dark except on pale base. Coxae dark. Trochanters paler than coxae. Tibiae pale, darkening near distal tip. Tarsi dusky or dark. Forewing with median vein once-forked. Abdomen: Cauda dusky, slightly spoon-shaped. Siphunculi dark, imbricated with flange. Marginal sclerites dusky. Pre-siphuncular sclerite absent. Postsiphuncular sclerite dusky. Marginal tubercles on abdominal II, III, and IV absent. Dorsum of abdomen with small transverse sclerites on VI, and VII and large transverse sclerite on VIII. Subgenital plate dusky and complete.

Type material. HOLOTYPE. Apterous vivipara. USA; Illinois; Lake County; Middlefork Savanna County Forest Preserve; on Pycnanthemum virginianum (L.) T. Dur. & B.D. Jacks. ex B.L. Rob. & Fernald 42.2620° N x 87.8962° W; 20.vi.2010; D. Lagos-Kutz. (INHS Insect Collection 511,252). Paratypes: 4 alate viviparae, 25 apterous viviparae, 511,243-510,259, Middlefork Savanna County Forest Preserve, 42.2620° N x 87.8962° W, Lake County, IL, 20.vi. 2010, on Pycnanthemum virginianum, D. Lagos-Kutz; 1 apterous vivipara, 511,363, Middlefork Savanna County Forest Preserve, 42.2620° N x 87.8962° W, Lake County, IL, 28.vi.2008, on Pycnanthemum virginianum, D. Voegtlin.

Biology. Two collections of alate and apterous viviparae females of A. elena were found in the summer (late June) of 2008 and 2010 on Pycnanthemum virginianum in Middlefork Savanna Forest Preserve, Lake Forest, Lake County, Illinois. The sexual morph was not found. It is likely that because the host plant is perennial, this aphid overwinters on the same host plant. Further observations need to be done to learn more about the biology of A. elena.

Etymology. This species is named after the first author’s daughter’s middle name, Katherine Elena.

Dichotomous keys to apterous and alate viviparous females of the Aphis that feed on Lamiaceae in the North American Midwest. The dichotomous key presented below is based on specimens from collections made in the Midwest (may not be reliable in other geographic regions), and molecular data for specimens from these collections support our morphologically based identifications. Morphological data for these species is shown in Lagos et al. (2014), Lagos-Kutz et al. (2014), and Blackman and Eastop (2006). For some comparative morphometric data of European specimens of A. fabae, A. gossypii and A. nasturtii see Stroyan (1984), Heie (1986), Brown (1989) and García Prieto et al. (2005).