124 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Legs pubescent, the posterior tarsi witli the lirst joint elongate, 

 joints 2-4 subequal. 



The majority of the species in this genus are minute and closely re- 

 semble those in AplwnogmuH Thoms,, although they are readily se[)a- 

 rated by the shape of the scutellum, which is broader, more flattened, or 

 subcouvex, without a frenum, the antennje in the males being filifoini, 

 not dentate or serrate, as in that genus. Apterous forms are <piite 

 common and will probably prove to be dimorphic forms of the winged 

 species. 



The records of rearings, with but few exceptions, show the group is 

 almost exclusively parasitic on the dipterous family Cecidomyid;e and 

 the homopterous family Aphididje. 



The species known to me in our fauna may be thus tabulated: 



TABLE OF SPECIES. 



FEMALES. 



Winged forms 2 



Wingless forms. 



Brownish yellow, the vertex of head fuscous C. fusciceps, sp. nov. 



Black, the base of abdomen pale or yellowish. 



Antennae, excep t scape at base, black C . MINUTUS Ashm. 



Whollj^ black, with wing pads. 



Legs golden yellow C. auripes, sp. uov. 



2. Wholly black 3 



Thorax and abdomen brownish yellow, the head black. 



C. MELANOCEPHALUS Ashm. 

 Head and thorax black. 

 Abdomen obscure rufous or piceous, yellowish at base and beneath. 

 Shining, but distinctly puuctulate ; scape rufous, the liagelluni black. 



C. PALLIDIVENTRIS, Sp. UOV. 



Polished, impunctured, angles of metathorax prominent ; antennie brownish- 

 yellow, 4 or ^ terminal joints black C. basalis, sp. nov. 



Head and thorax brownish yellow; abdomen black; base and apex of front wings 

 hyaline C. califorisicus, sp. nov. 



3. Head and thorax distinctly, closely punctate. 



Pleura aciculated; antenna; brown; legs browmish yellow. 



C. PUNCTATUS, sp. nov. 

 Head and thorax smooth, or the punctuation exceedingly delicate. 

 Antennae, teguhe, and legs black; pleura not aciculated; flagellum slender, 



the joints all longer than thick C. unicolor sp. uov. 



Antennae, tegulse, and legs brownish piceous; trochanters, tips of tibiae, and the 



tarsi yellowish white C. salicicola, sp. nov. 



Scape, teguliB, trochanters, knees, tibiae, and tarsi yellow; flagellum subcla- 



vate C. amplus, sp. nov. 



Scape and legs brownish yellow. 

 Tegulie black; flagellum black. 



Wings fuscous C. MELAnocerus, sp. nov. 



Wings subhyaline C. pedali.s, .sp. nov. 



Teguhe pale ; antennte brown, the scape and pedicel yellow ; pedicel longer 

 than the first flagellar joint, smooth, highly polished. 

 Wings hyaline; flagellar joints 1 to 5 transverse, 6 and 7 quadrate. 



C. FLAVISCAPUS, sp. nov. 



