442 STUDIES IN AUSTRALIAN ENTOMOLOGY, xvii., 



truncate club. Mentum wide; lobes wide, obtuse at apex; sinus 

 not deep.* Prothorax closely applied to elytra, subcordate, 

 widely margined; lateral margin without setse. Elytra ovate, 

 bordered at base, strongly striate; second and third striae uniting 

 at base, second striaf deep, extending to beginning of apical 

 declivity; third interstice impunctate, ninth seriate-punctate; 

 margin not interrupted near apex. Scutellum short, almost 

 covered by prothorax. Prosternum with anterior coxal cavities 

 closed; intercoxal declivity narrow, abrupt. Mesosternum with 

 intercoxal part wide, not channelled; mesepimera reaching coxae. 

 Metasternal episterna a little longer than broad, without apparent 

 epimera. Legs light, long; posterior coxse contiguous ; tibiae 

 slender, anterior a little thickened at apex, inner side emarginate 

 near apex, inner spur remote from apex; tarsi (9) slender. 



This strange genus is quite unlike any other of the tribe 

 Migadopini. I have ventured to tabulate the genera of Australia 

 and New Zealand below, but this has been done without having 

 a representative of the genus Nehriosoma before me (only the 

 type-specimen of N.fallax Cast., in the Howitt Coll., has been 

 reported as yet). 



Prothorax with narrow lateral border. 



Elytra seriate-punctate. (New Zealand) Amarotypus. 



Elytra strongly striate. (Australia and Tasmania)... Stichonotus. 

 Prothorax with wide lateral border. 



Mandibles short. (Australia) Nebriosoma. 



Mandibles elongate, porrect. (Australia) Decogmus. 



* The mentum, examined in situ, does not show the outline of the bottom 

 of the sinus clearly in my two specimens, owing to a gummy exudation, 

 but it appeared to be somewhat sinuous, and evidently without a median 

 tooth. 



fThis is a false stria, as in Stichonotus, representing the striole often 

 found at the base of the second interstice in Carabidse. In D. chalyheus, 

 it is as strongly developed as the other strise, and extends backwards an 

 unusual distance (a character found only in the tribe Migadopini), with 

 the result, that the elytra have ten interstices, if counted anyvihere before 

 the apical declivity, but only the normal number, nine, if counted near 

 the apex. 



