1903.] 223 



motionlessness), and if the position of its victim was favourable, it 

 pounced upon it immediately. Then the frog-hopper hopped ; in some 

 cases the fly lost it ; in some cases the fly re-appeared instantly from 

 the place to which the frog-hopper hopped. In one case I saw the 

 frog-hopper land with the fly still on its back ; I caught both, without 

 waiting, as perhaps I should have done. If the position was un- 

 favourable, or stems got in the way (<?. 7., Oeranium Roberfinnum), 

 the fly would circle round with its head towards the victim, like a 

 male DoUcJiopus, seeking a point from which to pounce. On several 

 occasions it failed to got a hold. Once a fly pounced on a frog-hopper 

 wJiicJi did not hop ; the fly immediately left it. Another came up and 

 looked at it, but went away without touching it. Was the frog-hopper 

 already entertaining an egg, or was it a male, or for some reason un- 

 suitable ? Chalnrus \ii i'ommon in my garden, but T have not been 

 able to see anything of its oviposition. 



These observations arc crude and inconclusive on several points ; 

 but I send them on the chance that others who can afford the time 

 will complete them. The flies are still common, and the frog-hoppers 

 now less scarce. 



10, Brookside, Cambridge : 

 July \Uh, 1903. 



SOME REMARKS ON HYDEOPORUS OEANVLARTS, L., AND 

 fir. BILINEATUS, Sturm. 



BY E. A. NEWBERT. 



In the June No. of this Magazine, Mr. A. J. Chitty brought 

 forward Hjidroporits biJineafus, Sturm, as an addition to the British 

 list. The opinions of recent authors concerning this insect are 

 various and conflicting. 



In 1881 Bedel (Coleop. Bassin de la Seine, i, p. 262, foot note) states that H. 

 biliiieaius, Sturm, ia tiie <? of granularis, L. In 1882 Dr. Sharp (Trans. R. Dub. 

 Soc, ser. 2, ii), in his valuable work on the Bytiscidce, gi\es both species, and states 

 that Bedel's view, just referred to, is erroneous. He describes H. hiUneatus as a 

 more elongate insect than granularis, with longer anterior tarsal claws and more 

 strongly dilated tarsi in the male, and some minor differences. In 1887 Dr. 

 Seidlitz (Bcstim. Tab. der Dytiseidae, Briinn, p. 63) makes no mention of any 

 difference of form, and separates the two species principally by the the first elytral 

 line reaching the base in //. bilineatus, not reaching the base, and being dilated in 

 front towards the side margin in the form of a hook, in II. granularis. As far as 

 I know, this is the most recent work on the subject. Sturm's original description 

 is not bad for the time at which it was written (1805), and he figures both species, 

 but exaggerates the difference in form. 



