WILLIAMS: HABITS OF WASPS. 227 



Family SPHECID^. 

 Palmodes mfiventris Cress, and Iseviventris Cress. 

 These are both active wasps about 20 mm. long. Both have 

 dark, smoky wings ; rufiventris has the abdomen reddish, while 

 Iseviventris is all shining black. Both of these wasps were 

 noted in western Kansas, where they preyed upon Stipator, 

 probably stevensonii, one of the Orthoptera of the subfamily 

 Decticinffi, or shield-back grasshoppers. 



Priononyx thorn le Fab. 



This is a quite common and rather slender wasp with sub- 

 hyaline wings, red abdomen, head and thorax more or less 

 ornamented with silvery pile, and with a length of about 

 15 mm. The insect has much the same habits as P. atrata, a 

 larger and entirely black species. Like the latter, thomse has 

 the habit of depositing her prey in a place of safety while she 

 excavates her one-celled tunnel. Of the two specimens ob- 

 served nesting, both secured a tryxaline locust for their bur- 

 row, one belonging to the genus Amphitornus, the other to 

 Aulocara. 



These wasps, at least in the male sex, in common with many 

 other Specidse, congregate in some numbers on weeds, where 

 they pass the night or remain during unfavorable weather. 

 Such "clumps" of wasps are a common sight on Russian thistle 

 in western Kansas. 



Priononyx atrata St. Farg. 

 PI. XXXIII, fig. 2, vertical section of burrow containing an Aulocara 

 locust; fig. 6, dorsal view of Melanoplus lakiviis, showing wasp egg (E) 

 in situ; fig. 7, o . 



A number of these very interesting shining black wasps were 

 studied afield. Their highly specialized habits are scarcely if 

 at all inferior to those of the well-known Ammophilas. 



P. atrata occurs plentifully throughout western Kansas, but 

 it was in the southwestern portion of the state that this species 

 was best observed. 



It preys upon several species of the short-horned grass- 

 hoppers or locusts (Acridiidse), insects always far weightier 

 than the wasp in question. Only one locust is stored in the 

 short, steep burrow. But the prey is captured before the nest 

 is begun (the contrary is true in all the Larridse I have ob- 

 served), and usually placed on some slight elevation,"* as a tuft 

 of grass, while atrata excavates her burrow. 



4, The Peckams have noted a similar habit in some of the Pompilidae. 



