568 



larger, and with different clothing on the under-surface. 

 N eocavonus niger and Phylliocephala nigrohirta have some- 

 what similar clothing, but are structurally very different. 

 The prothoracic cavity occupies fully half of the disc, the 

 tubercle on each side of it is fairly large and acute, and 

 projects slightly backwards, the apical tubercle is somewhat 

 larger, more acute, curved, and projects well over the head. 



Cavonus parvus, Blackb. 



PI. xxxiv., figs. 30, 31. 



This species varies considerably in size, the largest male 



in the Museum is 21 mm. in length; two specimens of the 



species were taken from nests of a soldier-ant (Myrmecia) at 



Port Lincoln. 



Cavonus armatus, Sharp. 

 PL xxxiv., figs. 27, 28. 

 Males and females of this species in the Museum, both 

 vary in length from 14 to 22 mm. 



Aneurystypus pachypus, n. sp. 



<$ . Bright-castaneous ; head somewhat darker and 

 opaque. Under-surface, legs, and pygidium with dense, 

 rusty-red hair; upper-surface glabrous, except for some long 

 hairs in gutters of pronotum. 



Head with coarse, crowded punctures between eyes, 

 becoming smaller and less crowded towards base, and absent 

 from a small medio-basal, polished space; clypeus with sides 

 and apex strongly rounded and elevated, suture well defined, 

 punctures at base as behind the suture, but becoming much 

 smaller in front. Antennae ten-, club three- jointed, rami 

 rather narrow, but slightly longer than head is wide. Pro- 

 thorax scarcely twice as wide as long, evenly convex, not 

 excavated or tuberculate in front, sides strongly rounded, 

 angles rounded off ; with fairly numerous distinct but not very 

 large punctures becoming somewhat larger and more numerous 

 on sides. Elytra slightly wider than prothorax ; with somewhat 

 irregular rows of distinct (but usually not very large) punc- 

 tures, usually in striae, these in places having a tendency to 

 become geminate, punctures about apex crowded and irregular. 

 Pygidium with crowded but partially concealed punctures. 

 Hind tibiae very short and strongly dilated to apex, spurs 

 stout and very unequal; claws long and thin. Length, 11-13 

 mm. 



Hob.— South Australia: Ooldea. Type, I. 7827. 



The unarmed prothorax and small size associate this 

 species with laetus, from the description of which it differs very 

 considerably in the punctures of its head and pygidium, and 



