OF PHILADELPHIA. 99 



black, thorax varied with reddish-yellow : elytra with several 

 longitudinal reddish-yellow lines, the exterior and interior ones 

 interrupted : feet pale testaceous. 



Length less than one-fifth of an inch. [154] 



This species, like many other species of this genus, varies in 

 the number of visible lines of the elytra and in their being more 

 or less interrupted, but the abbreviated lines into which they are 

 sometimes interrupted do not form bands, and at least one line is 

 continuous to near the tip, a character which distinguishes it 

 from the following species. 



[Previously described as H. catascojmim Say, Trans. Am. 

 Phil. Soc. 2, 103, and subsequently as JI. interruptus Say, ib., 

 4, 445.— Leg.] 



2. H. UNDULATUS. — Eufo-testaceous ; elytra blackish-oliva- 

 ceous, literate with testaceous. 



Inhabits Upper Missouri. 



Dytiscus undulatus Melsh. Catal. 



Body rufo-testaceous ; thorax, anterior margin black on the 

 middle, posterior margin black in the middle as far as opposite 

 the middle of the base of each elytron : elytra blackish, an irre- 

 gular marginal spot extends from the humerus to nearly one- 

 third of the length of the elytron, and obsoletely communicates 

 at its dilated middle with a band composed of two or three longi- 

 tudinal abbreviated lines, of which the inner one is subsutural ; 

 a smaller, marginal, irregular literate band behind the middle, 

 and an irregular spot at tip. 



Length more than three-twentieths of an inch. 



Found in a pond near Bowyer Creek, LTpper Missouri. It L« 

 not uncommon in Pennsylvania. 



P^EDERUS Fabr. 



P. BINOTATUS. — Beddish-yellow ; head, a part of each elytron 

 and the tail, black ; feet pale. 



Body pale yellowish-red, with numerous very short [155] 

 hairs ; punctured : head black, larger than the thorax : antennas 

 and trophi pale ; thorax longitudinally subovate, punctures dense : 

 elytra each with a large black spot on the exterior side towards 

 the tip : abdomen, terminal segment and tail black : feet whitish. 

 1823.] 



