246 CLASS INSECTA. 



Some have the antennae composed of eleven distinct articu- 

 lations, the external palpi filiform, or a little thicker at their 

 extremity, and the base of their posterior feet, as well as that 

 of the others, uncovered. 



Sometimes the thickness of the antennas gradually dimi- 

 nishes from their origin as far as their extremity ; the last 

 articulation of the labial palpi is simply obtuse at its extre- 

 mity, without emargination. Such are 



Dytiscus (Proper), 



In which all the tarsi have five very distinct articvdations, 

 and of which the anterior two have, in the males, the first 

 three articulations very broad, and forming altogether a pal- 

 let, either oval or transverse, or orbicular. 



D. Latissimus, Lin. Panz. Faun. Insect. Germ. 

 LXXXVI. i. Nearly an inch and a half long, and very 

 distinct by the compressed and trenchant dilation of the ex- 

 ternal margin of the wing-cases whose edge is yellowish. 

 The corslet is edged all around with the same colour. The 

 cases are furrowed and ribbed in the female. Found in the 

 department of the Vosges, in the North of Europe and in 

 Germany. 



D. Marginalisy Lin. Panz. ibid. 3. About one-fourth 

 smaller, having also a yellowish border all around the cors- 

 let, and a line of the same colour on the external and not 

 dilated edge of the wing-cases. Those of the female are fur- 

 rowed from their base, as far as about two-thirds of their 

 length. 



Fabricius tells us, that when turned upon its back, it re- 

 places itself by leaping, in its ordinary position. 



Esper preserved, for three years and a half, in a glass ves- 

 sel, a dytiscus of this species, and always in good health. 

 He used to give it every week, and sometimes oftener, a bit 

 of raw beef, about the size of a nut, whicli it would attack 



