204 Dr. David Sharp on 
account of the broad space over which the lines extend ; 
the limiting line between the retractile and the other 
part of the segment is also peculiar, consisting of a ring 
of deep depression. The scraping ridge on the hind 
margin of the post-nodular segment is also remarkable, 
being very fine and definite, and standing out in very 
evident contrast to the rugosities contiguous. Alto- 
gether this is a very remarkable apparatus. The struc- 
tures are in several respects similar to what exist in the 
Myrmicides, the shape of the band, its glossy surface, 
and the structure of the scraping organ being all 
Myrmicid. Fig. 4. 
PonERIDES.—Diacamma vagans, S8m., 3. Hong Kong. 
The retractile part of the second post-nodular segment is 
evenly covered with a dense, fine, reticulate structure, 
without any trace of a differentiated surface for stridu- 
lating. The hind margin of the preceding segment can 
hardly be considered to form a scraper, as it is scarcely 
more than a slightly projecting membranous edge that 
is somewhat minutely crenulate. 
As a sound producer, this is probably the most inferior 
Ponerid I have seen. 
PoNERIDES ?.—Cerapachys (Husphinctus),n.sp. (worker, 
quite blind). Baudin Island. The retractile portion of 
the second post-nodular segment is covered with a coarse 
sculpture similar to that of Ponera contracta, but there 
is no trace of any stridulating band; neither is there 
any differentiated stridulating edge or scraper on the 
preceding segment. 
This is a most peculiarly formed ant, the abdomen 
being of very unusual construction, each abdominal seg- 
ment being so formed that the limits so far as which it 
may be drawn into the preceding are exactly defined. If 
it possess a sound-making power, this probably exists on 
several of the segments, each of which has its hind mar- 
gin turned directly downwards, and tightly grasping the 
retractile portion of the following segment, so that when 
all the segments are drawn rapidly backwards and for- 
wards together or successively, a sound of a grating 
character may possibly be produced. 
I look on this as a very peculiar and yet very little 
evoluted form of ant. I have had a brief communication 
made to me about it by Prof. Forel, from which I judge 
this to be an ant the peculiarities of whose external 
