HORN EXPEDITION—ZOOLOGY. APPENDIX. 
413 
approached it, it kept sounding away in the distance, and was very evidently made 
by some bird. We came to the conclusion, which T think is the correct one, that 
the sound usually attributed to the .spider is in reality made by birds, and most 
probably by quails. The latter frequent the very parts—grassy flats amongst the 
hills—where the sound is heard and the spiders live, and they are most abundant 
just after rainfalls, when also the sound is heard most frequently. Not only this, 
but they actually produce a noi.se which is apparently identical with that 
attributed to the spider. The time spent in observing the animals was not, 
however, altogether thrown away, as one day, whilst teasing a large female which 
had been kept in a tin box for ten days, with a piece of straw, it raised its body 
and, rubbing its palps against the mandibles, made a distinctly audible whistling 
noise. The attitude assumed by the spider was much the same as that flgured 
first by Professor Wood JSlason,* and later still by Mr. Pocock.f 
On examining the animal I found that there was a very well-developed 
stridulating organ, consisting of modified surfaces on the inner face of the first 
joint of the palp and the outer face of the mandible. A short account of this 
was communicated in a letter to “Nature.” Meanwhile, Mr. Pocock’sj interesting 
article already referred to had appeared in “ Natural Science,” copies of which had 
not then reached Australia. Before this time Westriiig had described a stridii- 
lating organ, consisting of small teeth on the abdomen which scraped against ridges 
on the carapace, in spiders referred to the genus Theridium ; and Campbell^, many 
years subsequently, described an organ in Lephthyphantes formed from modified 
parts on the palp and mandible. Within the past few months further accounts 
of similar organs have been published by Mr. Pocock|| and by Mr. Pickard 
Cambridge.^ 
References to previous descriptions is given in these papers. All that need 
be said here is that so far two distinct sets of structures have been desci’ibed. In 
the one, the best example of which is that given by Mr. Pocock in the male of 
Cambridgea antipodia/id, there is an excavation in the abdomen with longitudinal 
ridges, which arc rubbed against by a scraper which has the form of a strong tooth 
placed on the pedicel. In the other set, what Mr. Pickard Cambridge speaks of 
as spines and keys, are developed on the palp and mandible, where they are in 
contact with one another. In some instances the keys are on the mandible and 
the spines on the palp (as in Phormingochilus )) in others the position is reversed 
» Tr.aiis. Entom. Soc., 1877. 
\ Nat. Sci., vol. vi., Jati., 1895, p. 48. 
t Nature, March, 1895. 
§ Journal Linn. Soc., 1881. 
II A.M.N.H., vol. xvi.. No. 93, p. 230. 
TI A.M.N.IL, vol. .xvi.. No. 95, p. 371. 
