174 THE ENTOMOLOGIST. 



herausgegebenen Insecten-Beliistigung,' iii. pi. 28 (1755)) under 

 the name of the " broad-bodied black-brown waterbug." * 



It is generally common and widely distributed all over 

 England, and the lowland parts of Scotland. It is the Ncpa 

 cimicoides of Linnaeus, the Nepa naucoris of De Geer, and the 

 Naucoris cimicoides of most authors. 



It is a somewhat lazy swimmer, though it can attain to a 

 very considerable speed upon occasion, and it often takes to w 7 ing 

 at night. It is very voracious, and, though generally vanquished 

 by the more powerful Notonecta, it is sometimes even the victor. 

 The imagines hibernate, and the ova are deposited at the end 

 of March or during April on leaves of water-plants ; they are 

 whitish, oblong, subcylindrical, obliquely truncate anteriorly. 

 They have been described at length by Eathke (" Studien zur 

 Entwicklungsgeschichte der Insekten," 1861, ' Stettiner Ent. 

 Zeitung,' xxii. pp. 172-4), who, however, gives July as the 

 month of deposition, and says that they are laid in somewhat 

 great numbers near one another on the under side of the leaves 

 of Polygonum amphibium. 



The method of oviposition seems to vary. Regmibart (1875, 

 Ann. Soc. Ent. France, pp. 204-6) states that an incision is 

 made in the stems of plants with the ovipositor, about 2 or 

 3 mm. long, and that the egg is enclosed about three-quarters 

 of its length ; one of the ends (corresponding to the cephalic 

 extremity of the embryo) is almost entirely free. Bueno, how- 

 ever, states that in Pelocoris the "majority have been found 

 attached axially to the stems or leaves of Ceratophyllum, and 

 secured to them by a glue in which the ovum is set, and which 

 surrounds the slender stem or leaf to a variable extent. The 

 adhesion is not very firm, however, and the ova are readily 

 detached." This corresponds to my own observations on Ilyo- 

 coris, as well as those of Dufour. I have also observed varying 

 conditions in Notonecta. 



The nymphs, which Eathke states feed on Confervas, are very 

 similar in all stages to the imago, the tarsi, however, being 

 unjointed, and the lateral margins of the abdominal segments 

 not produced spinoseiy. I have observed five nymphal instars, 

 thus agreeing with Bueno, who states that there are five in 

 the allied Pelocoris femorata, an American bug which he has 

 discussed recently ("Brief Notes towards the Life-history of 

 Pelocoris femorata, Pal. B., with a few Remarks on Habits," 

 1903, Journ. New York Ent. Soc. xi. pp. 166-73, text-figs. 1-2). 

 Bueno gives a total of about seventy-seven days for the meta- 

 morphoses, twenty-four of these being in the egg-state. t 



:;: It was also discussed by an old " pre-Linnean " author under the name 

 of Pygolampis lacustris ! (Johann von Muralto, 1684, ' Ephemerae Acad. Nat. 

 Curios, Dec. ii. Ann. ii. Obs. 80, p. 197'). 



f Extensive researches have recently been made by R. Heymons on the 



