1957] 
Christiansen — Collembola of Lebanon 
87 
Tibiotarsi with all setae uniformly ciliate. Tenent hair 
prominent and clavate. Unguis with basal teeth well de- 
veloped, one definitely larger, two unpaired median teeth, 
the apical one being very minute. Median teeth more 
prominent upon the hind unguis. Unguiculus acuminate 
and sparsely serrate along its posterior margin. 
Variation in dental spines: 22/19, 21/23, 22/21, 19/20, 
19/23. 
Known only from the type locality: Dog River Cave, 
Lebanon, July, 1951 on Debris 1 km. inside cave. 
Discussion 
This species is similar in many respects to T. orientalis 
but differs from this species in the shape of the mucro, 
the number and disposition of the dental spines, possession 
of a clavate tenent hair, the type of setae upon the anten- 
nae (see below), and the structures of the ungues. In 
this last characteristic the present species ressembles T. 
machadoi Delamare, but it differs from this form in most 
respects, most strikingly in the relative length of the 
mucro. 
The setae upon the antennae of these animals furnish 
an excellent series of characteristics. Unfortunately only 
three species were available for comparison but as the 
following table will illustrate, these indicated the value 
of further investigations of this characteristic. 
In addition to this the so-called sense organ of the third 
antennal segment differs among the three forms (axis 
central in ruffoi and lateral in the other two). 
seta type 
orientalis 
B 
D 
E 
stalk longer than apical 
expansion 
unilaterally finely ciliate 
F longer and definitely 
curved 
ruffoi 
longer, ciliation more 
prominent 
longer only slightly 
expanded apically 
dense mass upon apex 
of third segment 
straight 
* 
longer 
signifies similar to that illustrated for canis 
