Rev. H. Clark on the Dytiscidae and Gyrinidac of Australasia. 399 



Female. Length 5 linos. Black ; the head smooth and shining ; 

 the apex of the scape, the basal joint of the flagellum, and the tips of 

 the mandibles rufo-piceous. Thorax : the metathorax clothed above 

 and at the sides with silvery-white pubescence ; the coxse and femora 

 beneath with a thin ashy pile ; the wings subhyaline, the base of the 

 superior pair, a fascia in the middle, and a second and broader one 

 crossing at the marginal cell dark fuscous. Abdomen : the first seg- 

 ment with silvery pubescence above ; the third of a pale dull fer- 

 ruginous colour ; beneath, thinly covered with ashy pile. 

 Hub. Mexico. In the National Collection. 



2. Ferreola formosa. 

 F. nigra, pubescens, vertice, prothorace, mesothorace abdominisque seg- 

 ments tertio et quarto pube rufo-ferruginea vestitis ; metathorace 

 pedibusque pube alba ornatis ; alis fusco variegatis. 



Female. Length 1\ lines. Black ; the head above the insertion of 

 the antennas and the pro- and mesothorax above clothed with rich 

 fulvo-ferruginous pubescence; the metathorax with silvery- white 

 pubescence, the base and apex black ; the thorax beneath and the legs 

 with a silvery- white pubescence ; the tibia? and tarsi spinose ; wings 

 subhyaline, mottled and clouded with smoky stains, the apex of the 

 superior wings pale, as well as the base of the posterior pair ; a slightly 

 yellowish subhyaline band crosses the anterior pair at the first sub- 

 marginal cell. Abdomen : the first segment, the base of the second 

 laterally, and the entire under surface with a fine, thin, silvery-white 

 pubescent pile ; the second and sixth segments with an obscure-purple 

 lustre, the third and fourth with a rich rufo-fulvous pubescence. 

 Hab. Mexico (Oajaca). In the National Collection. 



This is one of the most beautiful species of the family Pompilidae. 

 The variety of its colouring, the brightness of the silvery pile that 

 covers the legs and other portions of the body, and its mottled wings 

 readily distinguish it from every known species of the genus. 



XXX. — Catalogue of the Dytiscidae and Gyrinidae of Australasia, 

 with Descriptions of new Species. By the Rev. Hamlet Clark, 

 M.A., F.L.S. 



I propose, in this and a subsequent paper, to notice the genera and 

 species of the Dytiscidae and Gyrinidae that are at present known to us 

 as inhabitants of Australasia — bringing together the few species that 

 have been described already by authors, and adding descriptions of 

 such new species as I have been able to examine, through the kindness 

 of Dr. Gray of the British Museum, Mr. Bowring, Mr. Waterhouse, 



