4 
Psyche 
[Mar. 
strangely enough, seem to be entirely missing on the 
chelicerae. Characteristic for these sensilla is their con- 
nection with two glandular cells which extend partially 
into the sensory duct. These cells secrete into the duct a 
substance which emerges at the surface after passing an 
end organ. P. Schulze assumes that the secretion serves 
as a protective coating against evaporation within the 
sensillum and on the outer surface, and also as a chem- 
ical means of recognition between opposite sexes and in- 
dividuals of one species. 
The sensory function of the sensilla auriformia seems 
to he of a proprio-receptive nature, serving to perceive 
changes or shifts within the chitin. It is probable that 
the other three types, grouped together as “tuft-shaped” 
sense organs or krobylophores, are vibro-chemoreceptive 
organs, which react at the same time to chemical as well 
as to seismic stimulation. They evidently play an im- 
portant part in the sexual life of the ticks. 
We examined the larvae of Rhipicephalus sanguineus 
Latr., Rh. appendiculatus Neum., Rh. bursa Can. and 
Fanz., Rh. evert si Neum., Rh. simus Koch, Hyalomma 
dromedarii Koch, and Boophilus calcar atus Birula. 
The larvae were merely mounted whole on microscopic 
slides in Berlese’s medium, a procedure which we found 
to be superior for our purpose to all other methods of 
mounting. Owing to prevailing conditions we were un- 
able to make sections. 
We were able to ascertain that the larvae are not 
equipped with peculiar integumentary sense organs. On 
the contrary we found much the same organs present as 
in the adults and nymphs. In the larvae, however, sen- 
silla laterniformia seem to be lacking and the other types 
of sensilla are to some extent more primitive in develop- 
ment. The organs are distributed over the entire body 
in fixed numbers and in a definite arrangement. 
A detailed account of the three types of sensilla men- 
tioned above follows. 
1. Sensilla sagittiformia (arrow-shaped organs) 
The sensillum sagittiforme represents a new mode of 
sensory organ, called by P. Schulze a krobylophore sen- 
