Smith. — On Mites attacking Beetles, etc. 199 



maxillary, the short anal fin, and the distance between the 

 dorsal and the caudal, as well as in its markings. 



Its eye is rather larger than usual, but I do not think that 

 it is the young of G. fasciatus, on account of its large maxillary 

 bone and the pale spot on the preoperculum, which is pro- 

 bably very constant in all ages of the fish. Also, G. fasciatus 

 is not known to breed in the sea in New Zealand ; the old 

 ones are never caught going down to sea, nor the young ones 

 going up the rivers. The only species of Galaxias in New 

 Zealand which breeds in the sea is G. attenuatus, and the 

 young, known as whitebait, ascend the rivers in spring in a 

 much earlier stage of development than the present fish. 



Art. XX. — On Mites attacking Beetles and Moths. 

 By W. W. Smith, F.E.S. 



[Read before the Philosophical Institute of Canterbury, 6th November, 



1901.] 



The late Mr. Maskell was the first to record* the occurrence 

 in New Zealand of the parasitic mite (Uropoda vegetans, De 

 Geer) attacking the introduced woodlouse (Porcellio scaber, 

 Latr.) and a native beetle. The beetle mentioned by Maskell 

 is a species of Elater, and generally known as " click-beetles," 

 from the click-like sound they produce when springing off the 

 ground. The larvae of several species of Elater have de- 

 stroyed enormous areas of gorse fences in New Zealand 

 during the last ten years by consuming the roots of the 

 gorse-plants. I have now to record the occurrence of Uro- 

 poda vegetans parasitic on eight additional species of beetles 

 and on two species of native moths. 



On the 8th September last Mr. Edwin Thomas, of Ash- 

 burton, sent me a specimen of Tricosternus antarcticus, a 

 large carnivorous ground-beetle, with many thousands of the 

 minute reddish-brown mites adhering thickly to every part of 

 the beetle's body. When the specimen reached me the mites 

 were so numerous that they completely enveloped its body and 

 legs so as almost to conceal it from view. They were nearly 

 Jin. in depth on its back, while on the legs, especially the 

 thighs and underparts, they were so matted together that it 

 was with difficulty the beetle could walk. An examination of 

 the parasite with the microscope showed it to be attached to 



* Trans. N.Z. lust., vol. xxv., p. 199. 



