351 



external, depressed submargin which is not, properly, a groove;) hairs 

 depressed. The external groove commences at about one quarter of the 

 length of the elytron from the base, the next to it is considerably longer, 

 the third from the margin is shorter than the second, but longer than the 

 first, and the submarginal groove is shortest of all. 



I have not the least doubt that this is the female of the above male, which 

 most closely resembles D. mediatus of Mr. Say. In the latter, of which I 

 have seen the sexes, the body is rather less obtuse in front, and the elytra 

 of the female are not sulcated, but plain like those of the male; and prob- 

 ably belongs to Hydaticus of Leach. 



Thofralernus is entirely distinct from the sulcatus of Europe, and with it, 

 belongs to the subgenus Acilius of Leach. It is described from nine speci- 

 mens of the male, and six of the female. 



D. *fascicollis. Convex, impunctured, pale testaceous ; vertical lunule and 

 base of the head, anterior and posterior thoracic fascite black; elytra black- 

 ish, irrorate with distinct pale yellow dots, the external margin and an 

 abbreviated subsutural line yellowish; a distinct dorsal series, and three 

 others obsolete of impressed setiferous punctures. Thorax of the female 

 obsoletely corrugated each side ; elytra smooth. 



Length eleven twentieths, breadth over six twentieths of an inch. 



Variety. Body beneath and feet pale piceous. 



Specimens seven. Is probably, referrible to Hi/daticus. 



D. *thoracicus. Pale rufo-testaceous, impunctured, oval, and somewhat 

 convex; head and thorax immaculate; external margin of the elytra pale 

 testaceous, disc blackish with confluent, black tortuous lines; three dorsal 

 series of punctures. Female with obsolete rugae on sides of the thorax ; 

 elytra smooth. 



Length nine twentieths, breadth nearly three tenths of an inch. 



Specimens seven. Appears to belong to Hydaticus. 



[New England Farmer, Vol. VII, No. xxi, p. 164, Dec. 12, 1828.] 

 CONTRIBUTIONS TO ENTOMOLOGY. NO. VI. 



Family Dytiscidcc, [Concluded.] 



The Dytisci are said to deposite their eggs in the bodies of dead aquatic 

 animals. Roesel states that they are hatched in ten or twelve days; the 

 larva comes to its growth the same season, when it leaves the water, and 

 forms for itself an oval cavity in the earth; in this it remains about fifteen 

 days before it becomes a pupa, and in fifteen or twenty days more it is 

 changed to a perfect insect. 



