412 



FAMILY XI. STAPH YLIXIDJE. 



TD4 (2415). Stenus alacer Casey. Rev. Sten., 1SS4. 135. 



Elongate, slender. Black, shining, very finely and sparsely pubescent: 

 legs dull yellow, very long and slender, the femora pieeous at tips; palpi 

 pale yellow. Head two-thirds wider than long, surface between the eyes 

 deeply excavate, sparsely and unevenly punctured and with a distinct me- 

 dian carina. Antenna? brownish, one-half longer than width of head, the 

 third joint one-third longer than fourth. Thorax subcylindrical. widest 

 slightly behind the middle, one-sixth longer than wide, coarsely, densely 

 and roughly punctate: Elytra at base as wide as head, suture slightly 

 longer than thorax : very roughly, densely and coarsely punctate. Abdomen 

 much narrower than elytra, tapering from base to apex ; coarsely and 

 closely punctate near base, finely and sparsely toward apex. Length 3.2- 

 3.7 mm. 



Posey County; rare. April 22. Taken from beneath mullein 

 leaves on a sandy hillside. A member of the Austroriparian fauna, 

 known from Florida. Texas and southern Illinois. 



Group IV. 



The members of this group differ from those of the preceding 

 only in having the fourth joint or tarsi distinctly bilobed beneath. 

 The abdomen is subcylindrical, usually tapering from the base and 

 without distinct side margins. The following species have been 

 taken or may occur in the State : 



KEY TO SPECIES OF GROUP IV. 



<(. Fourth and fifth abdominal segments wider than the first; length 4- 

 4.4 mm. AD VENA. 



act. Abdominal segments decreasing regularly in width from the base. The 

 fourth not wider than first. 

 b. Large species, 3.6 mm. or more in length. 

 c. Femora and tibiae not black throughout. 



d. Legs and antennas almost wholly pale dull yellow, the tips of hind 



femora alone darker; head slightly broader than elytra. 



795. elavicorx i s . 



dd. Legs black, the femora reddish-yellow at. base. 796. annularis. 

 cc. Femora and tibia? wholly black, the tarsi pale. 



e. Thorax equally wide at base and apex. tarsalis. 

 ee. Thorax distinctly wider at apex than base. 797. canadensis. 



bd. Smaller species, not exceeding 3.4 mm. in length. 



/. Legs pale yellow, the femora darker at tip ; length 3-3.2 mm. 



79S. CALLOSUS. 



ff. Legs dark fuscous brown in color throughout. 

 g. Thorax distinctly longer than wide. 



h. Elytra very slightly longer than thorax, their punctures very 

 coarse; length 2.8-3.4 mm. 799. arculus. 



hh. Elytra one-third longer than thorax, their punctures fine and 

 close; length 3-3.3 mm. 800. punctatus. 



gg. Thorax as wide as long; length 2.8-3 mm. hubbardi. 



