1921J NATURAL SCIENCES OF PHILADELPHIA. 291 



The female at hand differs from the description of that species 

 in the somewhat smaller size, with pronotum solidly suffused, leav- 

 ing only the lateral marginal portions pale and buffy, not rufescent. 



We have found that the species of £'^tb?a6erws are separable almost 

 entirely on features of coloration and color pattern. We know that 

 coloration is, as a rule, though by no means invariably, unsafe for 

 diagnostic purposes, while color pattern is often subject to decided 

 variation, particularly when marked individual recession or intensi- 

 fication occurs. Thus, mE. posticus (Erichson) and E .hi olleyi (Rehn), 

 the color pattern is decidedly affected by the latter factor, the gen- 

 eral type remaining the same. 



In argentinus we have a form showing the maximum extension 

 of the pronotal dark marking. Recessive examples will probably 

 show reduction of this marking, but we feel satisfied that the mate- 

 rial before us does not represent merely an intensive condition of 

 some other described species and we are of the opinion that the 

 pattern shown by less heavily marked individuals of argentinus will 

 exhibit distinctive features. 



Type: 9 ; Mistol Passo, near Icafio, Santiago del Estero, Argen- 

 tina. January and February. [Paris Museum.] 



Size and form, average for the genus. Head with interocular 

 space slightly narrower than that between the moderately large 

 ocelli, three-fifths as wide as that between the antennal sockets. 

 Antennae incrassate, moderately pilose. Pronotum with a distinct, 

 rounded angulation at point of greatest width meso-cephalad. Teg- 

 mina and wings fully developed, extending beyond the apex of the 

 abdomen a distance approximating the pronotal length. Supra- 

 anal plate delicate, bilobate. Subgenital plate simple, large and 

 chitinous. Ventro-cephalic margin of cephalic femora with (3 to 

 4) proximal and (1 or 2) distal heavy spines, between which is a 

 fringe of elongate hairs. Ventro-cephalic margin of median and 

 caudal femora armed with a single heavy distal spine. Ventro- 

 caudal margin of cephalic and median femora armed Avith two 

 heavy, closely placed distal spines. Ventro-caudal margin of med- 

 ian and caudal femora fringed with elongate hairs. Ventral margins 

 of caudal femora unarmed. Median and caudal femora with a 

 heavy, elongate genicular spine. Caudal metatarsus unarmed 

 ventrad, with a large pulvillus, rounded distad, linear and running 

 to near base of this joint; three succeeding tarsal joints with large 

 pulvilli. Tarsal claws simple, symmetrical. Aroha absent. 



Head and antennae chestnut brown, eyes prouts brown, ocelli 

 and mouth-parts ochraceous-buff. Pronotum almost solidly black- 

 ish chestnut brown, the moderately broad lateral marginal portions 

 apricot yellow. In the less intensively colored paratype the pro- 



