384 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



I obtained no other species from these nests, but cannot afKrm tliat no 

 other escaped.^ It may be a question, perhaps, whether the mud daubs 

 were made by Chalybion or Trypoxylon ; but we have the great authority 

 of the late Benjamin D. Walsh that the latter species is really a guest wasp, 

 not building and provisioning any nest for itself, but laying its eggs 

 in the nest built and jDrovisioned by the former, thus appropriating 

 for its own future progeny the spider store laid up by the industrious 

 Chalybion for its young. ^ It is curious and suggestive to trace this use 

 and wont from the guest wasp and the cuckoo up to the human species 

 as represented alike by the imperial " annexers " of Europe, Africa, and 

 the Orient, and tlie " land grabbers " of the Indian Territory, the " squat- 

 ter sovereigns" of the border, and the 

 " claim jumpers " of Rocky Mountain 

 mining districts. 



Among the wasps that provision 

 their nests with single spiders is the 

 common blue digger wasp, Chlorion 

 cieruleum Drury (Sphex), which, un- 

 like species hitherto alluded to, bur- 

 rows in the earth. It excavates its 

 egg nest in an incredibly short time, 

 sometimes consuming not more than 

 a minute or a half minute, and then 

 places therein a single egg together 

 with a spider, which is generally a 

 large one. With its front pair of feet 

 it then scrapes back the dirt which 

 it had withdrawn, frequently stopping 

 to pat it down with its abdomen. 

 When the hole is filled the surface 

 is smoothed to the level of the sur- 

 rounding soil. The large and beauti- 

 ful Elis 4-notata Fabr. (Scolia), (Plate 

 v.. Fig. 3), invades the burrows of 

 Lycosids, especially Lycosa tigrina, 

 and the small Priocnemus pomilius Cresson has been taken while carrying 

 a Laterigrade, a species of Xysticus, in its jaws. 



Another example of wasps that store single spiders is the large and 



beautiful Pepsis formosa Say (Pompilus), an inhabitant of the 



j_... Southwestern States of North America, where it is popularly 



known as the "tarantula killer." (Plate V., Fig. 2.) This 



name is given because of its habit of storing its burrow with that most 



' The figure here given (Fig. 320) was drawn from a series sawed out of a shed at Bell- 

 wood, Pennsylvania. - American Entomologist, Vol. I., page 133. 



Fig. 326. Series of " Pipes of Pan " mud daub cells, 

 from which escaped Trypoxylon politum. 



