10 
Psyche 
[ March 
produce information concerning its consistency in groups 
below ordinal rank. The absence of basipulvilli is charac- 
teristic of all the leaping Orthoptera and it is this factor 
which gives such a clear-cut division between the two or- 
thopteroid groups. The planta of Melanoplus is more heav- 
ily sclerotized than the representatives of Tettigoniidae and 
Gryllidae which were examined. 
Tettigoniidae — Ceuthophilus maculatus Say (Fig. 9) 
Except for the absence of arolium and basipulvilli, the 
condition of the planta seems to be the only important fea- 
ture of Ceuthophilus. This structure is not as heavily scler- 
otized as it is in Melanoplus and is quite different in shape. 
Often the planta is so lightly demarked, especially in small 
insects, that its boundaries are almost indistinguishable 
from the surrounding membrane. 
Gryllidae — Gryllus pennsylvanicus Burm. (Fig. 10) 
Gryllus gives us the first radical variation in the ungui- 
tractor for here the form is quite different from anything 
else found among the Orthoptera. This sclerite is charac- 
terized by a longitudinal V-shaped ridge or protuberance, 
the significance of which must remain in doubt until series 
are studied in groups below the order. It is possible that 
the less notable variations (chiefly in outline) of the ungui- 
tractor observed in these orthopteroid families will prove 
to be consistent to some degree. The planta may be easily 
compared with that of Ceuthophilus and differs mainly in 
the length of the lateral arms and the nature of the pos- 
terior margin. 
Gryllotalpidae — Gryllotalpa borealis Burm. (Fig. 11) 
Considerable modification of the planta is exhibited by 
Gryllotalpa and its condition in this insect is one of the 
factors suggesting a close relationship between planta and 
empodium. Note the numerous large setae and the manner 
in which the anterior portion of the unguitractor merges 
with the flexor membranes and planta. Comparison of the 
latter with the corresponding structure in Ceuthophilus and 
Gryllus indicates that it is a planta. 
Empodium by definition refers to a process of the ungui- 
tractor, but this term must also apply to certain structures 
