The legs of cave weta are equipped with various small spines, some along the length of each leg, others at the ends. The three pairs of legs each have three main parts femur, tibia and tarsus (foot). Spines that stick out at the ends of each femur and tibia can be helpful for telling genera (and sometimes species) apart. These are usually called apical spines
In the picture below there are two apical spines on the fore femur and two on the mid femur. In each case, the spines are on the side of the legs with one pointing forward (prolateral) and the other pointing back (retrolateral). You have to imagine that all the legs stick out sideways from the body, just as the middle legs usually do.
The table on the right gives examples. Particularly useful for small cave weta in North Island is the difference in spine combination shown by Neonetus and Isoplectron. The image on the left shows a species of Neonetus.