1908.] 221 



U. tuberculafm, Gvl! — This very distinct species lias been but 

 rarely taken in Britain. The best account of its occurrence is that 

 by Mr. Lennon (Ent. Mo. Mag., xxxi, p. 171), who took a single 

 specimen near Dumfries in May, 1895, with Agabus affinis, in a 

 shallow marshy place, far removed from any running water whatever, 

 in the middle of a fir wood much overgrown with long sphagnum. 

 On the Continent it is reputed to occur on peaty ground. 



H. rufiprs, Bosc— I never found this species in Norfolk, but 

 under the name cinereus, Marsh., it was recorded for that county by 

 Burrell (Trans. Ent. Soc. Loud., 1807, p. 207). Under the name of 

 the Turnip Mud-beetle it forms the subject of Leaflet No. 143 issued 

 by the Board of Agriculture and Fisheries. Attention was drawn to 

 it on account of the damage which it caused both in the larval and 

 imago states to turnips growing in Aberdeenshire. 



H. por cuius, Bedel. — Norfolk examples of this species stood in 

 my collection as ruqosus, 01. (rufipes Bosc.) from 18S2 until quite 

 recently. 



H. nubilus, Fab. — By far the commonest of the group to which 

 it belongs. 



H. alternans, Gene. — A submaritime species, sometimes abundant 

 in brackish ditches. 



H. aquaticus, L. — In the Colesborne district this species presents 

 practically no variation, but in east Norfolk one occasionally met with 

 examples in which the elevation of the alternate interstices on the 

 elytra is very strong. 



H. cequalis, Thorns. — This is what is known to British collectors 

 as the " small form " of aquaticus, than which latter it is a little 

 smaller with the surface of the elytra in the front half more even 

 and the sculpture of the thorax much more feeble on the disc than 

 at the sides. The material now at my command does not enable me 

 to form any decided opinion as to whether it should be regarded as 

 a distinct species or, as Ganglbauer puts it, an extreme form of 

 aquaticus; field observations would be of great value in this respect. 

 In all the specimens of reputed cequalis in which I have been able to 

 make an accurate measuremen of the joints of the hind tarsi I find 

 that the reduction in the size of the insect is accompanied by the 

 relative proportion of the second and third joints set forth in 

 Thomson's diagnosis ; and, in the few examples in which I have been 

 able to examine this feature, the denticulation of the free edge of 



