15G ADEFHAGA. [Haliplu^. 



tlireo miles from Dunifties, vvliicli is occasionally filled by the tides, in company with II. 

 riijicollis, and also by Dr. Sharp and Mr. Lennon in other localities near that town. 



These three insects are in all probability races of one species : the 

 extreme forms of H. ffuviatilis and H. ruficollis are very easy to distin- 

 guish, but, as Dr. Sharp (1. c. p. 81) and Mr. Rye (Ent. Ann. 1870, 44) 

 admit, intermediate forms occur which it is impossible to assign to 

 either ; the latter states that he found H. flttviatilis and ntficolHs in 

 great numbers in a running stream near Coombe Wood, accompanied by 

 specimens which he could not refer to either, and also by other extra- 

 ordinary vars. of the rvficollis type ; the conclusion he arrived at was 

 that the intermediate forms resulted from interbreeding between the ex- 

 treme forms, H. striatus would appear to be a constant variety, of the 

 intermediate type. 



K. lineatocolliS; Marsh. Eesembling in shape H. Jiuviatilis, but 

 not so much pointed behind ; at once distinguished by the dark longi- 

 tudinal line in the centre of the thorax, and the horizontal depression 

 at base ; the elytra are rather narrow, subj^arallel, with sculpture and 

 markings much as in the preceding species. L. 2| mm. 



Ponds and ditches ; also in clear water ; common and widely distributed throughout 

 the kingdom, as far north as the Moray district ot Scotland. 



CNEMZDOTUS, Illiger. {PeUodytes, Eeg.) 



This genus contains a few species, two of which are found in Europe ;• 

 the rest occur chiefly in North America : its members are easily distin- 

 guished from Haliplus by the longer terminal joint of the palpi, and 

 stand in much the same relation to that genus as Trechus to Bemhidium. 



The larva of C. impressus is figured by Schiodte, vi., PI. viii., Fig. 1 : it is perhaps the 

 most extraordinary of all the Coleopterous larva-, aud is remarkat)le for the absence of 

 spiracles, their place being taken by very long filamentous branchiaj which are jointed 

 aud are attached iu pairs to the dorsal segments of the thorax and of the abdomen (except 

 the ninth) ; they are not, however, inserted directly on the segment but on long 

 spinous processes such as are found in the larva of H.fulvus ; the anal appendage is 

 obsolete ; the ninth segment of the abdomen bears two very long jointed cerci, which 

 equal in length the whole abdomen ; the head is very small, appearing as a mere 

 transverse strip, and the legs are long and furnished with simple claws ; the colour is 

 dull and pale with tbe head and dorsal scuta somewhat olivaceous ; there are twenty- 

 two pairs of branchiffi, each branchia being as long as half the whole body of the 

 larva ; they are pellucid towards apex, and the trachea) may be easily traced in them 

 under a high power. If anything were needed to prove the distinctness of tbe 

 Haliplidse, the study of their larvai would certainly be sufficient without taking any 

 other points into consideration. 



C. impressus, F. {ca'sus, Duft.). Eeddish testaceous, elytra with a 

 greyish tinge ; head ditiusely punctured, mouth and base dark ; thorax 

 punctured in front and at sides, disc smooth, base with a rather deep 

 furrow which follows the course of the posterior margin, which is sinuous, 

 and is furnished with a more or less regular row of large black jiunctures ; 

 on each side of base there is a small stria or depression set in a black 



