SCIENTIFIC NOTES. 279 



it implies that they are chiefly to be found among reeds, sedges, and 

 such like aquatic plants. About ninety species of the group are known, 

 thirty of which are found in Europe, and nineteen of the number 

 inhabit this country. The larva; of the beetles feed in the stems 

 of their foodplant, and are seldom or never seen by the ordinary 

 collector. When full-fed, the larva; spin cocoons at the roots of 

 the plant in order to undergo their next change. Like almost all other 

 insects of this order, the duration of the pupal stage is exceedingly 

 short, but the beetles do not leave their cocoons for some time after 

 having attained the perfect condition, but remain in a state of 

 hybernation until the arrival of the warm sunshine, when they crawl 

 up the stems of the plants, and make their way out of the water. 

 Some species are to be found early in May, others in June, July, 

 August, September, and even as late as October. As previously 

 observed, they are essentially lovers of the bright sunshine, but the 

 month of the roses is certainly the most favourable time for obtaining 

 them, as they prefer the hottest weather wherein to take their sport 

 and pastime. At this period of the year, they may be observed by 

 anyone who cares to seek them, flitting from stem to stem in the 

 reedy places, or skimming over the broad floating leaves of various 

 water plants — the leaves of NympJicca alba and Potamogeton natans 

 being their special resort, and it is on the latter plants where I have 

 chiefly found them. 



The Biitish species are divided into two major groups by Fowler 

 {Coleoptera of British Islts), as follows : — 



1. Tibia; not produced externally into a tooth at apex; apex 

 of mandibles only slightly projecting beyond labrum ; first seg- 

 ment of abdomen longer than the rest taken together. 



2. Tibia; produced externally into a tooth at apex ; mandibles 

 stout, projecting considerably beyond labrum ; first segment of 

 abdomen equal to, or rather shorter than, the remainder taken 

 together. 



These groups are again subdivided into smaller ones ; but nearly all 

 our species vary so little in their general characters, and minute 

 descriptions are so bewildering, that it is far better for the young 

 student to find some distinct character by which he may know each 

 species. This will not prove a very difficult matter with this genus, 

 except in the case of I), sericea and D. discolor, which will be duly 

 dealt with in the proper place. 



The first species on our list is D. crassipes, F. In this species, 

 the posterior femora are very long, reaching to apex of elytra, the 

 insect generally dark in colour, and it has a flat compact-looking 

 appearance. Mostly found on the leaves of Nympluea alba. A few 

 years since, the late Rev. H. J. Gore took a great many at the New 

 Forest, some of which he kindly gave me. Several localities are given 

 by Stephens and Fowler, in England, Scotland, and Ireland ; the 

 species seems widely distributed, and other localities may also be found 

 by the ardent explorer. 



D. dentata, Hoppe. — Said to be closely allied to D. crassipes, but 

 the general build of the insect is very different ; it is much more 

 robust in shape, and could hardly be confounded with the latter 

 species. The colour also is much more variable, some being of a 



