MUTILL^E OF NKW HOLLAND. 
21 
DIAMMA, IVestw* (In Proceedings of Zool. Soc., April 14, 1835.) 
Corpus elongatum nitidum apterum, tbomce in medio constrictum segmentisque abdominis 
basi subcoarctatis. Caput subhorizoiitale fere rotundatum. Clypeus (fig. 6 a) medio 
longitudinaliter carinatus, antice in lobum transverstim, super labrum productus. Labnim 
margine antico ciiiato. Jlandibul® longa) curvaUo falentae, intus ct ante apicem acutum 
dcutibus tribus aequalibus annatte. Maxillm (fig. 6 b) lobo extemo tenui margine 
rotundato ; palpi maxillarcs graciles 6-articiilati articiilis 3 ct 4 longioribus. Mentuni 
comeum (fig. 6 c) elongatum labio in apico ejus retractile. Palpi labiales 4-articulati 
articulis intermediis obconicis. Antenna) breves convolutaj 12, articulatas articulo 2ndo 
mimUo,apicalibu8 gracUioribus. Thorax quasi binodosus. Nodus anticus fererotunda- 
tus e collori raaximo constans. Mesonotum in annul um brevem angustuiu contiactuua. 
Mesosternum majus, obliquum, ct pedes intcrinedios gerens. iSIctatliorax magnus nodum 
posticum thoracis constituens et spiraculis duobus lateralibus instructus. Abdomen 
oblongo-ovalc subdepressnm segmeuto basali ad apicem constrictum. Pedes breviusculi 
spinosi unguibus bifidis (fig. 6 d). 
The very interesting insect, which is the type of this genus, is 
closely allied to Mynnecodes Latr., or the females of Thynni and 
to Myrmosa Latr. The peculiar toothing of the mandibles, is, 
however, quite unlike that of those insects, whilst the elongated 
maxillary palpi ai’e still more unlike those of the female Thynni, T. 
variabilis $ for example, in which the maxillary palpi are extremely 
short and apparently only 3-jointed, a peculiarity overlooked by 
Dr. King in his ilemoir on Thynnus, although it is one which 
would have caused him to hesitate previous to sinking all the genera 
established by M. Guerin. I am unwillingly prevented at present 
from entering into this part of the subject so fully as it deserves, 
and shall only add that, in the females of Myrmosa, Methoca, and 
Mutilla, the palpi do not differ from those of the males, which is 
also most probably the case in Diamma. The very slight pilosity of 
the body of the type of this genus, its polished surface, articulated 
thorax, and bifid ungues, are all characters which it, however, 
possesses in common with the female Thynni; which appear to me 
to be its nearest allies. 
Spfxies l.—Diamma bicoior, AVestw. (Plate 54, fig. 6.) D. tota purpurea, cyaneo, yel 
fflneo uitens, antennis pedibus mandibulisque rufis, his ad apicem nigris. Long. corp. m. 
pi. 
Habitat in Terra A"an Diemenii. In Mus. nostr., &c. Communic. Dr. Ewing, &c. 
M. Guerin has described a female insect from Kangaroo Island 
(in the Voyage de la Coquille, texte, p. 235,) under the name of 
“Di’amma epliippiger; Apterus, nigei’ nitidus Imvigatus mesothorace, 
metathorace pedibusque fulvis.” Like D. bicolor ?, it has 6-jointed 
maxillary palpi, but the mandibles have only a single tooth within, 
and Mr. Shuckard assures me that this insect is the female of 
Rhagigaster unicolor, an insect which differs considerably from 
Psamatha. 
