i949 j Dinnik and Zumpt — Rhipicephalince 9 
cept that we were unable to discover the two foremost 
pairs on the ventral side and that they seem to be missing 
also on the fourth and fifth festoons counting from the 
middle. 
The larva of Hyalomma dromedarii Koch (Text-fig. 
2) possesses more sensilla hastiformia than that of Rhipi- 
cephalus. It should be mentioned especially that the 
middle festoon also bears a terminal and a dorsal un- 
paired sensillum. In addition a sensillum hastiforme is 
located on the dorsal side adjacent to each of the second, 
third and fourth festoons. It is noteworthy that two 
pairs of sensilla hastiformia, instead of one pair, were 
found on the capitulum of one specimen in the position 
of the arese porosse of the adult female. 
3. Sensilla auriformia (ear-shaped organs) 
The sensilla auriformia discovered by P. Schulze 
(1942u) in adult ticks may be traced back with certainty 
to setae or hairs. They are located directly under the 
cuticula and consist each of a flat disk, usually inclined 
a little toward one side, so that it closes outwardly the 
sensory duct ascending from below, like a lid with over- 
lapping edges (PI. 1, fig. 3). The disks vary in details 
and have the shape of an ear, a megaphone or a bell. 
Their openings face various directions, so that it is pos- 
sible to see one sensillum in direct view and the other in 
side view when examining two of them placed close to- 
gether. 
The larval ticks also possess these sensilla in typical 
form, but the organs are smaller than in the adult. The 
disk is approximately 0.009 mm. in diameter. Arrange- 
ment and number again seem to be strictly uniform, but 
all the disks lean in one particular direction. 
Ten pairs of sensilla auriformia were found on the al- 
loscutum of all larvae of Rhipicephalus examined. Five 
pairs may be seen dorsally some distance from the 
median line and five pairs on the edge of the alloscutum. 
Neither capitulum nor scutum seem to have any. Twelve 
pairs are located on the ventral side, two of them be- 
