2 [June, 



DESCRIPTIONS OP SOME NEW SPECIES OF THE GENUS 

 PACHYTRICHA. 



BY D. SHARP, M.B. 



Among the many interesting and anomalous genera of Goleoptera 

 that inhabit Australia, the genus PacTiytricJia is probably one of the 

 most remarkable. Its satisfactory classification is a difficult point, 

 and I think must yet remain so. Hope considered the genus allied to 

 Olajjliyriis and Chasmatopterics ; Erichson considered it to be an ally 

 of Eucliiriis, but afterwards changed this opinion, and placed PacJiy- 

 tricha among the group of Sericoid Melolonthce, of which numerous 

 genera are found in Australia, one or two in Western South America, 

 one or two in New Zealand, and one in Europe. This group of 

 Sericoid Melolonthce, as established by Erichson, and adopted by 

 Lacordaire, consists of a series of genera differing greatly one from 

 another, and the association of which in one group does not satis- 

 factorily express their differences and affinities. It must be admitted 

 that Pachytricha in its general appearance, and in numerous points of 

 its structure, differs much from all the other genera of the group ; and, 

 if we bear this in mind, and recollect also, that the other genera to 

 which it has affinities, viz., GlapJiyrus and Euchirus, are also very 

 anomalous, and of difficult classification, I think we are warranted in 

 concluding that we are here dealing with a genus which is less 

 Bpecialized than most of the other genera of Lamellicorn Goleoptera, 

 and one therefore which is, perhaps, the little changed descendant of 

 one of the more primitive forms of the family Scarahceidce. 



I have examined the position of the abdominal stigmata in the 

 Bpecies characterized infra as P. minor, and adjoin their description, as 

 well as some points that have escaped observation in the anatomy of 

 the genus. 



Abdominal stigmata two, thi'ee, and four, similar in shape to one 

 another, moderately large, very open, elliptical, stigma three rather 

 larger than two or four. Stigmatd two and three placed partly in the 

 connecting membrane, and partly in the horny portion of the abdomen ; 

 stigma four placed just in the horny portion close to the membrane ; 

 etigma five placed also close to membrane, its position being similar to 

 that of the fourth stigma, but it is smaller than that, though it is 

 large and open. Stigma six is small and closed, scarcely quite so 

 near the membrane as the fifth stigma, but yet very little distant 

 therefrom. Stigma seven small, placed close to junction of the dorsal 

 and ventral plates. 



