296 PROCEEDTNOS OF THE NATIONAL MUSEUM. vm.: xxxi. 



with some exceptions on the cl3'^peus in these insects. Still coarser 

 punctures are the places of origin of coarser hairs, or of liairs perhaps 

 little coarser than those forming pubescence, but standing- erect and 

 not so close to each other but that the nature and color of the plate 

 beneath can be seen. These hairs seem in most cases to reach their 

 greatest size on the clj^peus, particularl}^ in Proterosphex, where thej'^ 

 are almost bristles, erect, but with their outer portions bent downward. 

 At different places on the bod}' they vary in length and ainmdance, 

 being longest usually behind the lower part of the eyes, and on the 

 end and sides of the median segment. 



Besides punctures, the surface of the ])ody frequently shows parallel 

 ridges or grooves, varying from fine to coarse. Whether they are 

 ridges above the general surface of the plate or grooves in it, it is often 

 difficult or impossible to determine. When in doubt the terms "striate," 

 "stri»," or "rugose" have been used. Where these markings occur 

 the punctures are usually in rows between them rather than on the 

 ridges. Occasionall}', particularly on the mandibles, elongated punc- 

 tures resembling short grooves are found, cither scattered or more or 

 less in rows. These are termed "aciculations." 



The colors present are limited, but the shades are numerous and 

 perplexing. Black, ferruginous, and yellow are the leading colors, 

 with every intermediate shade present in one or another species. The 

 head and thorax are usually the location of the black, if present, while 

 the abdomen may be partly black, partly ferruginous, entirely ferru- 

 ginous, or even entirel}' yellow. The ferruginous is ver}^ variable in 

 shade, ranging from a dark rich color resembling that of clear pieces 

 of resin through lighter shades to a clear j^ellow. Where the thorax 

 is black the legs and petiole tend to be black also, and in the case of 

 the former when this fails the basal segments at least (coxse,* trochan- 

 ters, and bases of the femora) are liable to be black, as are the tips of 

 the claws, while the mandibles are usually black, though it is not 

 unusual, particularly in species having more or less ferruginous on the 

 body, to find a ])and of this color on the mandibles also. 



The wings, frequently hjaline, sometimes have a 3'ellow tinge, par- 

 ticularly on the basal half. The outer margin is often darker, as 

 though somewhat smoky or fuliginous, and in man}' cases the entire 

 wing is fuliginous, and ma}' even be so densely so as to be nearly 

 opaque. Accompanying this increase of the fuliginous is an increase 

 in a reflection color seen at certain angles. In North American forms 

 this is usually bhie or violet, but in many South American species it 

 is distinctly greenish. 



Pubescence is generally yellow and often golden, almost metallic in 

 its luster. If not yellow it is white, moi'o or lessjsilvery. A sericeous 

 surface may be dull black, brown, gray, yellowish, whitish, etc., accord- 

 ing to the color of the minute hairs causing it, and a covering of this 

 nature often conceals the color of the chitinous plate beneath. 



