314 



allow of its confident identification without examination of the- 

 type but the description (so far as it goes) and locality suggest 

 lineatocollis. If so, I doubt whether it can stand permanently in 

 Ditoma on account of the very decidedly expanded and denticu- 

 late lateral margins of its pronotum the extreme edge of which is 

 not bounded (as it is in Ditoma crenata) by a raised edging. I 

 do not however know of any other described genus in which it 

 can be placed. 



D. lineatocollis, Blackb. It is not improbable that this name 

 will have to sink as a synonym of serricollis, Pasc. (discussed 

 above). 



D. costata, Mac]., and torrida, Blackb. These must be trans- 

 ferred to the genus Phormesa. 



D. pulchra, Blackb., obscura, Blackb., and nivicola, Blackb., 

 appear to be congeneric with the New Zealand species D. sellata, 

 Shp., attributed by its author doubtfully to Ditoma. Dr. 

 Sharp, however, thought it might be congeneric with species for 

 which Broun had, without giving a diagnosis of the generic 

 characters, proposed the name Ahlahus. I have examined the 

 descriptions of the species in question and think Dr. Sharp's 

 conjecture probably correct, and am disposed to refer my three 

 species named above to Ablahus. They differ from Ditoma in 

 having the lateral margins of their head and pronotum strongly 

 expanded and indented, by the presence of antennal sulci, and by 

 their much more strongly granulate eyes. They are very near 

 Sparactiis, but the sides of their head and pronotum are much 

 more strongly dilated and indented, and the club of their 

 antennie has only two joints. From Phormesa they difier by 

 the indented margins of their head and pronotum, their non- 

 carinate elytra, the longer sulci for the reception of their 

 antennae, and their much smaller eyes. M. Grouvelle has 

 suggested doubtfully Endophhfus for them, but the apex of their 

 tibia? undoubtedly has a small spine, which is inconsistent with 

 EndojjhUfus. 



D. perforata, Blackb. This species cannot stand permanently 

 in Ditoma, owing inter oMa to the form of the antennal club, 

 the first joint of which is very much larger than the other — the 

 latter being little more than rudimentary. M. Grouvelle has 

 suggested to me that the insect might be placed in Synchitay 

 which also has the apical joint of its antennae rudimentary. 

 (According to Lacordaire the 11th joint is altogether wanting, 

 but to me it seems in *S'. juglandis, Fab. — the type of the genus 

 I believe — to be distinctly visible, though very small). 

 D. perforata would, I think, be as aberrant in Synchitaj as in 

 Ditoma, owing to the sides of its prothorax being strongly 

 dentate and its eyes more coarsely granulate and much more 



