ART. 9 DIGGER WASPS OF GENUS PODALONIA FEENALD O 



four on the side proper, one on the laterally projecting angle of the 

 segment at its outer end, and two on the end between the one last 

 mentioned and the articulation of the next tarsal segment. In some 

 species, despite variations, these seven spines are long and maintain 

 their diameter nearly to the end, which often appears almost squarely 

 cut off. Between and around the four long spines on the side, other 

 ordinary ones are usually present. Of the four, the first is liable to 

 reduction to about half the length of the others but is often full size. 

 These spines appear to be used as scrapers by the insects in digging 

 holes where their prey and eggs are deposited. Claws are nearly 

 always (always?) light, ferrugineous or even lighter colored in some 

 cases. None of the North American species have toothed claws. 

 The pulvillus is usually large but is greatly reduced or absent in 

 luctuosa. 



SURFACE CHARACTERS 



The surface markings on the various skeletal plates show much of 

 interest. Nearly every plate bears a smaller or greater number of 

 indentations or pits (termed punctures), more or less circular in out- 

 line, not as deep as the diameter of the hole at the surface. From the 

 bottom of each pit grows a hair, so that the abundance of clothing 

 of an insect can be determined by the abundance of the punctures, 

 even with specimens in which most of the hairs have been worn off. 

 Where the punctures are circular in outline the hairs stand erect, 

 though their outer half may be curved ; where the pit enters obliquely, 

 giving it an oval outline, the hairs come out obliquely. Different 

 sizes of punctures are paralleled by different sizes of hairs growing 

 out from them. Pubescence, in the sense used by the writer, does 

 not occur in this genus as a rule, except on the clypeus and lower 

 part of the frons in the males. Here the punctures are small, close 

 together, oblique, and the hairs coming from them are decumbent, 

 forming a smooth, continuous covering lying close to the plate itself. 



A still finer grade of marking is so minute that its details are 

 hardly perceptible without higher powers, but with a pocket lens or 

 low powers of the microscope a sort of " bloom," suggesting that on 

 a ripe plum, is evident. Where this is found, the plate beneath shows 

 very fine markings which some writers have indicated by describing 

 the surface as "shagreened." This appears also to consist of the 

 most minute punctures, out of which come very minute, decumbent 

 hairs which show on the body much better at some angles than at 

 others. In some cases, if not viewed at the proper angle, they can 

 not be seen at all. A surface described as sericeous is one produced 

 by the tiny hairs just mentioned. Brownish or grayish sericeous is 

 often met with on the antennal filament and elsewhere. 



