Key to females of North American species of Trachytes

The key is based on the illustrations and descriptions of Błoszyk & Szymkowiak (1996), Huţu (2000), Koch (1841), Trägårdh (1910) and WiŠniewski & Hirschmann (1994). Two species of North American Trachytes are known only from males ( T. krantzi Huţu, 2000 and T. lindquisti Huţu, 2000), and are not included in the key.

1. Vertex with wide and ribbed lateral sections................................................................. 2

- Vertex without wide and ribbed lateral sections.............................................................. 5

2. Inguinal shield free, not fused to ventral shield.............................................................. 3

- Inguinal shield fused to ventral shield...................................................................... 4

3. Surface of genital shield smooth, setae X4 placed on ventral shield....................... T. aegrota (C. L. Koch, 1841)

- Genital shield with reticulate sculptural pattern, setae X4 situated on small platelets in membranous cuticle................................................................................ T. kaliszewskii Błoszyk & Szymkowiak, 1996

4. Genital shield linguliform, apical part wider than basal part, proportion of apical and basal parts of genital shield 1.3–1.5: 1. 5

- Genital shield axe-shaped, apical part narrower than basal part (3:1)......................... T. canadiensis Huţu, 2000

5. Pygidial shield rhomboid; surface of genital shield smooth............................... T. aegrotasimilis Huţu, 2000

- Pygidial shield oval; surface of genital shield reticulate....................................... T. californica sp. nov.

6. Genital shield linguliform, anterolateral angles of genital shield rounded......................................... 7

- Genital shield axe-shaped, anterolateral angles of genital shield pointed...........................................8

7. Ventral shield separated from inguinal and sternal shields; surface of genital shield ornamented by irregular pits............................................................................. T. balazyi WiŠniewski & Hirschmann, 1994

- Ventral shield fused with inguinal and sternal shields; surface of genital shield smooth............ T. marilynae Huţu, 2000

8. Inguinal shield fused to ventral shield; apical part of genital shield relatively wide (apical: basal = 1:1.3–2).............. 9

- Inguinal shield separated from ventral shield; apical part of genital shield narrow (apical: basal = 1: 3)....... T. axe sp. nov.

9. Sternal shield fused to inguinal and ventral shields; ventral and dorsal idiosoma ornamented by irregular pits.............................................................................................. T. minima Trägårdh, 1910

- Sternal shield separated from inguinal and ventral shield; surface of ventral and dorsal idiosoma without irregular pits.......................................................................................... T. nortoni Huţu, 2000