Nicholls — Two New Vhrcatoicids. 
185 
apparently luider^oing' degeneration. Tlie jlrfit antenna (PI. XXV, 
Pig. 2, 2a) reinai'kahly slioid with, in the female, ftovcT joints than 
in any speeies of Tlivvatoienn deserilnnl liitlierto. There is very little 
to distinguish the pediimde from tlie liagellnm, the penultimate joint 
of the latter being, in the female, relatively large and swollen, while 
the terminal joint is a mere knob. In the full gi'own male there may 
be either four or five joints, the second and^ third being subcqual 
and larger than the other joints. Setae are not very abundant, bnt 
there is a small terminal tuft and an olfactory eylinder occurs upon 
both the terminal aid the i)enultimate joint in lioth sexes.* The 
second antenna (PI. XXV, fig. 1, and Ph XXIX, hg. 44) is sliglitlv 
less than half the lengtli of the body, th<^ ])eduiu4e, witli five joints, 
being almost exactly half the length of the flagellum, which has 
eighteen to twenty long, slender, joints ea(4i set with a sub-terminal 
and incomplete circlet of setae; in the peduncle the first joint is 
short, the second, third and fourth increase ])rogressively in length, 
the fifth being slender ami as long as the third and fourth together. 
The i(]}}>er li/) agrees closely with that of P. austndis (Chilton, 
1891, p. 156, PI. 24, fig. 4). The mandihlcs, also are much as in that 
species, the right mandible having but three teeth in the cutting 
edge. The spinous plate, however, on both mandibles (PI. XXVI, fig. 
12, 12a) is a curved structure Avith a median grooAu^ running along 
its exposed face, on either side of AA’hich is a roAv of stout s])ines 
Avith Avell marked denticulations ; on the left mandible these spines 
(16-18 in number) ajipear to be symmetrically arranged and similar, 
but on the right the s])ines along one edge (the posterior), 
are smaller and shar])ly bent. Retween this plate and the molai’ 
tubercle are the usual ])ectinate setae (tAvo or three). On a level Avith 
the tubercle are a numl)er of short stiff setae. T^pon the palps some 
of the stoutest setae (PI. XXVI, fig. 12, s) are strongly serrate on 
one margin and fi'ijiged AAuth fine closely set hairs on the opposite 
edge. The lower Up (PI. XXVI, fig. 9) differs apparently from that 
of P. australis chiefly in that its inner margins are clothed Avith 
longer and stiffer setae. 
The jirst maxilla (Ph XXVI, fig. 8, Sa) also resembles closely 
that appendage in J\ ausiralis. fts outer lobe is broaif Avlth truncate 
apex set Avith eight or nine stout setae, some of AA’hich are denticulate. 
The inner lobe has the usual number (4) of ])lumose setae, agreeing 
in this A\dth P. sheplmnU, P. lirlii and P. assimilis, P. ausfredis is 
*ln Ph XXI, Pig. 1, the length of the first antenna, relatiAT to the 
second, has been exaggerated — ^in its natural position, its apex 
rarely reaches the terminal joint of the peduncle of the second 
antenna, its total length only eipialling the combined length of 
the three terminal joints of the peduncle of that ai>pendage. 
