Key to Timema in North America

This key is adopted from Vickery (1993). Timema is a genus of small, stubby, wingless, brown or green walking sticks which are found primarily in California.

Two species are known to be parthenogenic, T. genevievae and T. tahoe. No males are known from those two species. No females have been collected (at the time of Vickery's paper, anyway) of T. ritensis and T. dorotheae.

Male Timema:

1	Left cercus is bifurcate with arms acutely angled apically; intra-dextral processes twisted	2
	Left cercus with apices of arms not acute; right cercus apically truncate or emarginate, arms obtusely angled or rounded; intra-dextral process variable but not twisted	3
2	Both right and left cerci bifurcate, both arms acute at apices; outer arm of left cercus nearly twice as long as inner arm	T. chumash
	Arms of right cercus short, broadly rounded; left cercus with both arms apically acute, outer arm not more than one-quarter longer than inner arm	T. nakipa
3	Left cercus broad basally, narrower and strongly curved inward to apex	T. cristinae
	Left cercus narrower at base than apically	4
4	Bifurcate arms of left cercus with at least the apex of the internal arm broad or narrowly rounded; intra-dextral process oblique apically with acute apex	5
	Left cercus not bifurcate; may have inward-facing projection; intra-dextral process variable, usually bent toward the left cercus	6
5	Left cercus with two basal inward-facing projections; large species	T. knulli
	Left cercus with only one basal inward-facing projection	T. californicum
6	Left cercus oblique apically with two very shallow indentations and with prominent conical, basal projection	T. nevadense
	Left cercus broadening toward apex; with either small apical indentations or inward-facing subapical projections	7
7	Intra-dextral process curved towards left cercus but not strongly bent, base of process broad	T. boharti
	Intra-dextral process strongly bent	8
8	Left cercus broad at middle, narrow at base	T. podura
	Left cercus broad at base and increasing in breadth gradually to apex	9
9	Intra-dextral process slightly rounded apically	T. ritensis
	Intra-dextral process nearly truncate, obtuse-angulate	T. dorotheae

Female Timema:

1	10th tergum broadly rounded apically	2
	10th tergum truncate, emarginate, or bifurcate	3
2	Green specimens (a few may be brownish)	T. chumash
	Brown specimens	T. podura
3	Green specimens	4
	Brown or gray-brown specimens	8
4	Cercus long (2 mm dorsal measurement)	T. knulli
	Cercus shorter (1.5 mm or less)	5
5	Cercus truncate apically with visible teeth	T. cristinae
	Cercus not truncate apically	6
6	Cercus apically truncate on upper half, rounded beneath	T. tahoe
	Cercus oblique apically	7
7	Cercus with prominent apical teeth and with distinct dorsal tooth	T. nakipa
	Cercus with or without very small apical teeth	T. californicum
8	Cercus rounded, oblique in lateral aspect	T. genevievae
	Cercus not oblique apically	9
9	Cercus broadly rounded apically	T. nevadense
	Cercus truncate on upper half, broadly rounded below	T. boharti