WATBE-BEETLBS. 223 



8. emarginatus is the only representative of the genus 

 Spercheug. It is a very rare insect — so rare, indeed, that for 

 some time it was thought to be extinct as a British beetle. 

 It was formerly found in Whittlesea Mere, Kensington Gardens, 

 and at Windsor; but rather lately, I believe, it has been 

 discovered near the South of London. The female is said to 

 inclose her eggs ia a pouch, and carry them about aflSxed to 

 the Tinder-part of her body. The eggs are hatched in about 

 ten days, and as soon as the young larvse appear, the busy 

 and prolific mother immediately commences a new cocoon 

 to contain more eggs. But notwithstanding the fecundity 

 of this insect, it is not only rare in this country, but also on 

 the Continent. This interesting beetle has been described 

 by the author of the " Coleoptera of the British Islands " 

 as having the power, both in its larval and in its perfect 

 state, of walking upon the under-surface of the water, in the 

 same way that many of the aquatic snails do. 8. emarginatus 

 is about im. long, and is of a yellowish-brown colour. Its 

 head is flat and almost black. Its elytra, which are wider 

 than the thorax, are spotted with brown; its legs are reddish; 

 and its palpi and six-jointed antennae (the last five joints of 

 which form a club) are yellowish. The larvse of this beetle 

 are said to be so full of air that they seem to have quite a 

 difficulty in sinking in the water. 



The seven species of small beetles which are comprehended 

 in the genus PMlhydrus are in shape rather similar to the 

 Hydrobii. Their length varies from ^in. to iin., and their 

 antennse are nine-jointed, the last four joints forming a pointed 

 club. Their bodies are long and convex, and in appearance 

 seem more like those of terrestrial than aquatic insects. 



The Berosi are yellowish and very convex insects, and 

 are about ^in. in length. Their thoraces are ornamented 

 with a spot of beautiful metallic colour ; their eyes are very 

 prominent, and their antennae are eight-jointed, the last 

 three joints forming an obtuse club. The four species belonging 

 to the genus Berosus are B. luridus, B. oericeps, B. spinosus, 

 and B. affinis, most of which are fairly common. B. spinosus 

 possesses a short spine near the apex of its elytra ; hence 



