572 HYDROMETRINA. 



Head black, with fine short hairs. Antennas black, finely pubes- 

 cent. Eyes and Ocelli black. Rostrum ; 1st and 2nd joints dusky 

 yellowish, the 2nd with a black line down the middle ; 3rd black. 



Thorax. Pronotum reddish-brown ; behind the anterior angles, 

 on each side in the fovea, a large subrhomboidal spot, sharply angu- 

 lated in front and rounded behind, clothed with shining, clear white 

 pubescence; between these spots, close to the anterior margin, a 

 transverse, dull, orange line, from the middle of which a short, 

 raised, orange line usually juts out posteriorly; the undercurved 

 side-margins, and below them to the sternum, orange ; disk ante- 

 riorly with a few, posteriorly with more, distinct, small, black punc- 

 tures ; Metanotum, in apterous examples, with an orange spot in the 

 centre. Elytra brown-black, with 4 clear white spots ; the 1st long, 

 narrow, sublinear, at the base close to the anterior margin ; the 2nd 

 oval, at the base of the 1st cell (when the elytra are closed these 2 

 spots are close to the sides of the scutellar process) ; the 3rd and 

 4th round, one behind the other on the middle of the elytron. Wings 

 fuscous, with darker nerves. Sternum at the sides, with very fine, 

 long, yellowish hairs ; Pro- and Mesosternum dull, dusky yellowish, 

 fuscous outwardly ; Metasternum brown-black ; coxal sheaths out- 

 wardly black, with a silvery gloss, inwardly yellowish-brown, the 3rd 

 pair with the posterior margin yellowish. Legs black, brownish 

 beneath, clothed with close, short pubescence ; the middle tibiae with 

 a row of very fine, long, projecting black hairs ; tarsi brown. 



Abdomen above, black, with a faint orange middle line, the sides 

 with a row of long white spots, 1 on each segment, the 1st 2 being 

 larger than the others ; underside orange, with fine, very close 



pubescence, each side with a row of connected, large angular spots, 

 broadly margined interiorly with glossy silvery pubescence; Con- 



nexivum orange, the posterior outer angle of the 1st 5 segments with 



a triangular black spot, the projecting point of the 6th also black. 



Genital segments black, with very short projecting hairs. 

 Length, 3 3{- lines. 

 The apterous form is common in small companies, on clear 



streams, from March to September ; the winged form is rare. 



