Found on Douglas fir (Pseudotsuga menziesii), along with one other male and 3 females...all nymphs (so no mate-guarding "piggy-back" riding behavior yet).

Two of the 3 female nymphs appear in the posts thumbnailed below:

       

These were T. poppense...from the stripes, Doug fir host, location, and presence of males (eliminating the "look-alike" all-female parthenogenetic species T. douglasi).

I found that the diagnostic 'darker green medial and lateral stripes' of T. poppense (present in all members of the population here) could get somewhat obscured (i.e. washed-out) by flash photography...but those stripes were clearly evident on all these Timema. The stripes help these Timema blend in with the pale & dark longitudinal striping present on the bottom of the Douglas fir leaves/needles (where the pale stripes correspond to stomata).

Note that in immature males, the dextral(=right) cercus and (nascent) intra-dextral process are enclosed within a thin sheath and appear as a single appendage.