Jh'ilish S/wr'ifs of lhi\\\>\nf*. 115 



ns sufficiently distinct to be calltnl a vaii<ity, and my chief 

 ii'asoii for not sopuratini; it ;is a species is tliat in tlic form o£ 

 tlio 8edea<(ns and its ncct-ssoiy lobes the two are identical. 

 Now all the other species of this ii^roup are to lie distin^ui.'jhcd 

 on the wdea^al characters, and noma.v ami ^</-ou;//ea«M.s- cannot 

 therefore be re<>;arded as of the same s'liiviinfi^ towards ono 

 another as either of them is to any of the other species. If 

 they are to be regarded as separate species, they must form a 

 distinct genus or subgenus apait from the others, and there 

 is not sufficient justification for this. 



J/. Homa.c is, so far as is at present known, a northern and 

 \vestern form occurring in the following counties and vicc- 

 countits: — Ireland'. Antrim, Down, and Oarlow. Scoiland: 

 Clyde Isles (Arran and Bute), Rjnlrjw, Lanark, Ayr, and 

 Kirkcuilbright. Kiu^hnul: I have set'u a ^ of the s[)ecie3 

 from L» dsham, Ciieshire, tak"U by W. E. Sharp, but thai; 

 was before " hrowneniiis" had been sciKirat-d, and I dj not 

 know to which foim it beloiif^ed. Otherwise there is, so far, 

 110 English record for the type. 



It is a lake-species, found most abundantly in i!ilay and 

 June, but continuing to occur until August or even Sep- 

 tember, chi' fly in the n;ore stony parts, it, however, also 

 occurs — though never abundantly — in rivers and canals 

 where stony comlitions may be absent, but where otherwise 

 some lake conditions exist, such as large volume of well- 

 oxygenated water and equable temperature. 



The variety has so far oidy occurred in Bucks and Ea^t 

 Anglia (Cambridge antl Norfolk E.), where it seems to be 

 almost confined to rivers and broad drains of sloM'-moviug 

 water, though I found it the dominant llali[)lid in one or two 

 large and deep ponds in an old clay-pit near Cambridge. 



Jj. nomox varies somewhat in general form, usually being 

 widest a little behind the shouldeis; but in some cases the 

 elytra are almost parallel for some distance back, while in 

 others the widest point is about halfway back. The var. 

 hrowneanus is ajiparently less variable, the form being widest 

 a little behind the shoulders and more acut(^ at the apex than 

 in normal nomax. The thorax is slightly longer in propor- 

 tion to its width, and tlie sides are less strongly convergent 

 anteriorly than in the type. The insect is rather smaller 

 than most nomax, and is rather more brightly coloured, 

 owing to the dark elytral lines being narrower and the 

 ground-colour pale yell )W instead of testaceous. The usual 

 elytral marking both in nomax and the variety reminds one 

 oi' fiiivititilis more than of any other species. 



In both the type and the variety the basal segment of the 



' 8* 



