DORCFS. 79 



the seventh joint sometimes drawn out into a sharp supjjie- 

 mentary process. Head in females (and occasionally in 

 males) very short behind the eyes, so that the latter are close 

 to the front angles of the ])rothorax, sometimes lengthened 

 behind the eyes in the male, the posterior ])art then sometimes 

 a little swollen beliind the eyes or producetl into a blunt or 

 ])ointed process. Eye generally divided by tiie canthus in 

 front, rarely (/>. rugosus, etc.) almost completely divided, 

 but the canthus never com})letely united witli the cheek. 

 Clypeal process various, generally tongue-like in the female, 

 pointed, rectangular or cleft in the male. Maxilla long, tiie 

 inner lobe bearing a horny hook in the female but not in the 

 male. Mentum large and broad, naked, covering the ligula, 

 which consists of two narrow nxl-like diverging branches, 

 bearing long hair-fringes anteriorly, the labial palpi with the 

 first and third joints long and the second short. 



This genus, i)rotean in its outward aspect, at least in the 

 male sex, but fairly homogeneous in its essential characters, 

 is one of those aggregates which remain in nearly ever}' large 

 family of insects when tlie more circumscribed groups of species 

 have been generically defined and separated. It has often 

 happened that man}' of the individual forms composing such 

 a mass of closely related si)ecies have, ui)on their fiist discovery, 

 been considered generically distinct and given names accor- 

 dingly but contiiuial discovery of other forms filUng the gaps 

 in the series I'enders the subsequent abandonment of many 

 such names inevitable. The striking nature of the features 

 distinctive of many of the nuiles in tlie present family has led 

 to a particularly liberal creation of generic names based only 

 upon those features, which, as a result of their invariable 

 inconstancy, are usually wanting in small specimens of the 

 male sex, as well as in all specimens of tiie other sex. For 

 this reason, 1 have been obliged to treat as synonyms of 

 Dorcas a considerable number of names hitherto accepted as 

 valid. Attempts have been made by Tliomson (Ann. Soc. 

 Ent. France, 18(32, \). 421) and by GraVely (Rec. Ind. Mus. xi, 

 . 11)15, p. 407) to define certain of these according to the form 

 of the prosternum or of the clypeal process, but the latter, 

 in addition to bemg very inconstant, is of use only for the 

 males and the study of many more s])ecies than were known 

 to these authors has shown that both features are found in 

 every stage of transition. Unwillingness to abandon names 

 which are no longer useful often leads, as an alternative, to 

 the introduction of still more names and consequently to ever 

 increasing confusion. 



It has not ev'cn been j)ossil)le to retain the existing grouping 

 for subdividmg the genus Doicus, the great differences generally 

 found between the two sexes making features taken from the 



