268 B. GRASSI AND A. SANDIAS. 
parts, which possess no other form of nerve-ending, such as 
cones (Kegel) or papille (Zapfen). These hairs are espe- 
cially numerous on the apex of both pairs of palpi and on the 
antenne ; on the latter they are most abundant on the apical 
half of the terminal joints. There appears to be no marked 
difference between the sensory hairs of the mouth parts and 
antenne, and experiment shows that the latter organs are 
constructed so as to remain functional even when deprived of 
a certain number of joints. 
(3) The tibize exhibit the peculiar sense-organs discovered 
by Fritz Miller,! evidently tympanal organs (PI. 19, fig. 10). 
This is shown by the presence of the usual terminal rods, of 
a characteristic tracheal branch, the lumen of which is not 
accurately cylindrical, and which opens at either extremity 
into the main tracheal trunk of the tibia, and lastly, of tym- 
panic membranes. 
Tactile hairs are present on various parts of the body, and 
the so-called abdominal appendices (cerci) also appear to be 
essentially tactile. These appendices are really identical with 
the caudal cerci of Thysanura, reduced to a short basilar piece 
and a long terminal joint, of which the apical extremity is 
glabrous. ‘The remainder of their surface is covered with very 
long, fine, and readily vibratile hairs, in addition to others, 
such as are scattered over the body. 
The description just given of them goes to show that they 
correspond in Calotermes with those found in other insects. 
All the sense-organs here described, with the aforesaid excep- 
tion of the eyes, are fully developed at the time of hatching. 
The visual structures are certainly more or less imperfect ex- 
cept in the adults, and become functional concomitantly with 
the wings. Their unimportance in other stages is evident from 
the fact that pigment may be either present or absent in the 
eyes of substitute royal forms, and that individuals without, 
or with more or less imperfect eyes, apply themselves equally 
well to the work of the colony. 
[Calotermites move their antennz freely, and employ them 
1 [‘ Jen. Zeitschr.,’ ix, p. 234, pl. xii, figs. 32, 34.] 
