1876.] 9 [Austin. 



most ready means of separating them. Col. and Ariz. (Coll. 

 Horn.) 



3. Paederus riparius Linn. (Staphylinus), Faun. Suec., No. 

 846, etc. 



I have only seen a single specimen of this European species in 

 Dr. LeConte's collection, who remarks that it is doubtfully Ameri- 

 can. It is larger than any of our species except the two mentioned 

 above, 0.30 in. 



4. Paederus littoreus Zimm., Ms. 



A single specimen from S. C. Head black, with a large median 

 smooth space, and only a few large punctures on the sides and base. 

 Antennas, mouth parts, legs, thorax, first four segments of abdomen, 

 and whole under side of body excepting the fifth and sixth abdominal 

 segments, red. Thorax narrowed behind, sides nearly straight, all 

 the angles rounded. Elytra blue, about as long as the thorax, spar- 

 ingly punctured with large shallow punctures irregularly placed, but 

 a little more dense on the sides. Abdomen sparingly finely punc- 

 tured, fifth and sixth segments black, beneath coarsely, sparingly 

 punctured. 



5. Paederus compotens Lee. New sp. Am. Col., 48. 



I have only seen the type in LeConte's collection ; the antennas 

 are slender, only slightly thickened externally, and joints eight to 

 ten not transverse. Underside sparsely and finely punctured. Sac- 

 ramento Valley, Cal. 



The four following species are smaller and very closely allied. 



6. Paederus palustris. 



Head black, orbicular, smooth and shining, with a few rather large 

 punctures on the sides, in front between the eyes a deep fovea on 

 each side containing several punctures. Antennas as long as the 

 head and thorax, first four and last one to three joints red, interme- 

 diate joints varying from dark red to black, thickened externally, 

 third joint less than one and one-half times as long as the second, 

 fourth about equal to second, following joints to the tenth gradually 

 shorter and thicker, eighth to tenth transverse, eleventh obliquely trun- 

 cate and acute on the lower side. Mouth parts red. Thorax red, 

 round oval, very convex, equally narrowed before and behind, disk 

 with a row of small punctures each side, and a few scattered ones 

 near the sides; from each puncture proceeds a black bristle. Elytra 

 blue, not longer than the thorax, sparingly punctured with shallow, 

 broad, punctures. Abdomen with the first four segments red ; termi- 



