NO. 1487. NORTH AMERICAN DIGGER WASPS— FERNALD. 29V) 



here aciculations, are often present, and on the upper and lower (inner 

 and outer) borders a row of quite long, stiff hairs is often seen. 



The antennte are quite long and are usually carried in a somewhat 

 curled position. The basal portion or bulb of the proximal segment 

 or scape is very small and articulates with the head in a socket. Its 

 diameter at this end is about equal to its length to where it unites with 

 the enlarged portion of the scape, but it narrows rapidly till, at the 

 point where it enlarges into the scape proper, its diameter is but little 

 more than half that at the base, the narrowing being mainl}^ on one 

 side. The bulb has ever}- appearance of being an entire segment, but 

 as this is not the generally accepted view it is here considered as a part 

 of the scape. The scape is the stoutest portion of the antenna. It is 

 often ferruginous or partly so, when the remainder of the antenna is 

 entirely black. Smallest at its base it enlarges rapidl}' and suddenly 

 constricts close to its articulation with the next segment, the pedicel, 

 the increase in diameter, as in the case of the l)ulb, being chieHy on 

 one side. It generally bears a number of hairs, most abundant 

 internally, which may in some cases be even so coarse as to almost 

 entitle them to be termed spines. The pedicel which articulates with 

 the scape proximally and the first segment of the filament distally is 

 a short, subglobular segment, sometimes differing with the scape in 

 color, from the remainder of the antenna, though more frequently 

 of the same color as the filament. It also frequentW bears numerous 

 small hairs most abundant on the inner face. Kohl appears to con- 

 sider the pedicel as the first segment of the filament. The filament 

 consists of ten segments in the females and eleven in the males. 

 These segments are generally longest proximall}^, being there two or 

 three times as long as broad, and the first one is usually the longest. 

 The ends of the segments are slightly larger than elsewhere and the 

 articulations are all somewhat oblique to the axis of the segments. The 

 terminal segment at its tip appears almost as though cut ofi', the end 

 being very abrupt. In the male there are two or three longitudinal 

 ridges on each filament segment except the first and last (eleventh) 

 with depressions between. At the outer end of each of the segments 

 these ridges appear to be more or less joined to each other, so that any 

 two would have somewhat the outline of the letter U. Traces of these 

 ridges may also be found on the distal end of the first and basal part 

 of the last filament segments. The surface of the filament, particu 

 larly its outer half or two-thirds, is frequently sericeous, caused l)y 

 the presence of a dense layer of short, decumbent, very minute hairs 

 which may give the surface a dull black, dull brown, or other color 

 quite different from that of the chitin which always seems when 

 unclothed to have somewhat of a luster. (Plate YIII, fig. 12.) 



Prothorax. — The prothorax is naturally divided into two parts—the 

 slender, more or less elongated portion which articulates with the 



