western Pennsylvania and Washington Lists, but does not appear in 

 the New Jersey List. 



A. amplus new species. 



Size large, form regularly ovo-elliptical, the prothorax and elytra perfectly con- 

 tinuous in outline. Color black, moderately shining, faintly aenescent, elytra with 

 a small sublateral yellow spot behind the middle ; mouth, antennae and legs dark 

 rufous, body beneath rufopiceous. Head nearly two-thirds as wide as the pro- 

 thorax, the latter more than twice as wide as long, side margins unusually broad. 

 Reticulation of upper surface moderately fine, the areolae irregular and unequal, 

 the reticulating lines with numerous fine punctures which occur for the most part 

 at the intersections. Coxal plates large, the length of the metasternum between 

 them and the mesocoxal cavities only about one-third their own length. Hind 

 tibiae with a row of five or six punctures along the inner margin. Pro- and 

 mesotarsi of male quite distinctly dilated and rather strongly compressed, the 

 anterior protarsal claw thickened and sinuate beneath but without tooth. Length 

 11.5 mm.; width 6.25 mm. 



Described from a single pair, submitted by Mr. Sherman. The male 

 type retained in the Sherman collection is from Missouri : it was 

 obtained from Oberthur and bears the name "brevicollis Lee" in 

 Oberthiir's hand. The female bears label "Kentucky, Sanborn." 



Our largest species of Agabus and evidently quite a rarity. In addi- 

 tion to the tabular characters it may be distinguished from its nearest 

 allies by the more broadly margined thorax. In neither of the two 

 specimens at hand is there any trace of the rufous occipital spots which 

 are normally present in stagninus and semivittatus though sometimes 

 quite obscure. 



A. obtusatus Say, Trans. Am. Phil. Soc. II, 1823, p. 99. 

 ? nitidus Say, 1. c. p. 98. 



Broadly obtusely oval, polished black, elytra with apical and postmedian sublateral 

 yellow spots. The lines of the elytral reticulation are very fine and lightly im- 

 pressed, the areolae large, irregular, unequal, and each as a rule with one or more 

 minute punctules. The length of the metasternum between the middle coxae and 

 the coxal plates is scarcely more than one-fourth of the length of the latter. The 

 male tarsi are only narrowly incrassate, the protarsal claws virtually unmodified, 

 though on close inspection the anterior one may be seen to be faintly sinuate be- 

 neath. Length 7.3 to 8. mm. 



This species ranges from Canada through the New England States 

 as far south as the District of Columbia, and west to Iowa and Lake 

 Superior. It superficially resembles rather closely semivittatus, but is 

 rather smaller and more obtusely oval, and is otherwise easily separated 

 by the tabular characters. It is most closely allied to planatus, which 

 see for further comparison of characters. 



A. planatus Shp. On Dytiscidae, p. 503. 



Very closely related to the preceding species, from which it differs as follows : 

 The size is slightly greater, the color less deeply black, but rather inclined to be 



12 



