520 Mr. D. Sharp and Mr. F.-Muir on the Comparative 



formed by two pieces articulated together, the distal one bearing 

 two small lateral lobes. It is possible that the distal piece is the 

 basal part of the lateral lobes, and the basal plate is the basal 

 piece. The basal corners of this basal plate meet under the 

 median lobe. No differentiated internal sac. 



Chaetosoma scaritides (PL LVIII fig. 98). 



Median lobe slender, cliitinous on ventral aspect, membranous on 

 dorsal ; median orifice on dorsal aspect of tip, ventral edge pointed 

 and projecting beyond dorsal edge. Tegmen forming a ring, with 

 large dorsal cap-piece formed of a large curved plate with a pair of 

 broad lateral lobes at apex ; the ring is broad and continued as 

 a strut {kj) on ventral side. Internal sac small, not differentiated. 



There are probably more than one species of Chaetosoma 

 in New Zealand, and if so the one here dealt with is 

 not the C. scaritides of Westw. Ours is a comparatively 

 large, black form, found by Commander J. J. Walker at 

 Wellington. 



Bhizophagus dejyressus (PL LVIII fig. 101). 



Median lobe large, tubular and slightly curved ; median orifice 

 at apex, the base prolonged into a long dorsal strut. Tegmen 

 forming a slender ring round the median lobe, the dorsal part 

 slightly enlarged into a very small cap-piece. Internal sac large, 

 with stout, twisted flagellum arising from apex. 



This differs from Nitidulidae by the large, exposed 

 median lobe, the cap-piece of the tegmen reduced so as 

 not to cover the lobe. 



This family is of great interest and requires much 

 greater investigation than we have given it before any 

 definite conclusions can be arrived at. It will eventually 

 have to be divided. Whether or not certain divisions that 

 have already been proposed are adequate we cannot say. 

 Chaetosoma is of interest as it shows a probable transition 

 from the sheath type (Trogositidae) to the true ring type. 

 In Diagrypnodes we have a type nearer to Pythidae than 

 to Cucujus. The degree of differentiation of the sac and 

 the condition of the lateral lobes must be considered 

 in adjusting the relationships in this family. Thus 

 Hectarthrum has a more generalised tegmen than Bhizo- 

 phagus wherein its reduction to a mere ring is very 



