THE <JENUS HESPERIA. 141 



The Genus Hesperia, {With three plates.) 



By T. A. CHAPMAN, M.D. 



{Continued from page 95.) 

 Dr. Eeverdin associates with H. carthami two species of which I have 

 no male specimens, hieti and oherth'uri ; whether these are like carthami, 

 close to the cacaliae group, I do not know, but since Dr. Beverdin 

 regards them as very close to carthami, it seems tolerably certain that 

 they must be so. The cacaliae group are specially characterised by the 

 "style" being rather long and slender and ribbon-like, close to its 

 origin it makes a fold as if bent over, and looks as if one ought to 

 straighten it out in mounting the preparation, this, however, is not 

 feasible, the bend is the normal condition, and is not the result of 

 pressing down flat a process that is merely curved. The style beyond 

 this bend is straight and directed distad. The clasp in carthami is very 

 like that of this group, say alpina, but differs in the style being solid 

 and rounded., not flat and ribbon-like, and without bend or fold. Dr. 

 Reverdin's figure of the armature of H. cashtuirennis (of which I have 

 no specimens) shows the clasp to be nearer that of H . carthami than 

 to that of H^ cacaliae, in which group Dr. Eeverdin places it. The 

 leading point of resemblance being that the stjde, instead of being flat 

 and bent as in H. cac-aliae, is rounded, at least comparatively, the small 

 scale of the photograph prevents one being sure there is not some flat- 

 tening, and is without bend. It may certainly be taken as connecting 

 the two groups, or rather as welding them into one, which seemed 

 otherwise a reasonable result to arrive at. 



The cacaliae group has one peculiarity of wing marking, that occurs 

 also in carthami, and is very pronounced in sidae, in some respects an 

 outlying member of the cacaliae group. This is the special form of 

 the discal spot beneath the forewing. In most Hesperias this is a 

 definite spot, with definite outline like any of the other well-marked 

 spots, but here its outer margin is blurred and is produced as a light 

 cloud on the portion of the wing beyond. In the photograph of under- 

 sides in pi. ix. :(by Mr. A. E. Tonge), this is well seen in that of 

 ■cacaliae, where the pale cloud is seen, but hardly any spot ; compare 

 this with alvetis (fig. 1), where the definiteness of the spot is well seen 

 on the left side (right of picture). In carthami the tendency of the 

 spot to lose its clear outline and extend outwards in a cloudy area is 

 well seen on the right underside. This cloudy extension of the discal 

 spot appears to be fairly constant in all examples of the H. cacaliae 

 group. In other species of the more European sections the rule is to 

 be without it, but it occurs as a frequent variation in some species, 

 more usually as a radiant line or two along the veins. It occurs again 

 in some species of the more Eastern section, which are only very dis- 

 tantly related to the fd. cacaliae group. 



Dr. Eeverdin is the first to point out the fact that H. sidae is a 

 member of the H. cacaliae group. This is at once obvious when one 

 notes the general structure of the appendages, the form of the tenth 

 iSternite and the bent ribbon-like style. 



That we always regarded H. sidae as a very special form, probably 

 hardly related to our other European Hesperias, results from the ten- 

 dency, so difficult to avoid, to be dominated by points that are super- 

 JuLY 15th, 1917. 



