in FOSSORES 101 



an extremely rare American Insect that had previously been placed 

 by Cresson among parasitic Hymenoptera. Westwood classed 

 RJiopalosoma among Diploptera, saying of it " animal quoad 

 affmitates excrucians." We reproduce Westwood's figure, but not 

 being acquainted with the Insect we can express no opinion as to 

 whether it is allied to the Scoliidae or to the Sphegidae. The 

 habits are, we believe, quite unknown. 



Fam. 2. Pompilidae. 



Pronotum at the sides reaching the tegulae ; hind body never 

 definitely pedicellate, though the first segment is sometimes 

 elongate and conical; hind legs long ; eyes elliptic inform, 

 not emarginate. 



The Pompilidae are perhaps the most extensive and important 

 of the groups of Fossores, and are distributed over all the lands of 

 the globe, with the exception of some islands and of the inclement 

 arctic regions. The sting of the Pompilidae, unlike that of most 

 of the Fossores, inflicts a burning and painful wound; the creatures 

 sometimes attain a length of two or three inches, and a sting from 

 one of these giants may have serious results. Although there is 

 considerable variety in the external form of the members of the 

 group, the characters given above will enable a Pompilid to be 

 recognised with approximate certainty. The elongation of the 

 hind legs includes all the parts, so that while the femur extends 

 nearly as far back as the extremity of the body in dried 

 examples at any rate the tibiae and the long tarsi extend far 

 beyond it ; thus these Insects have great powers of running ; they 

 are indeed remarkable for extreme activity and vivacity. They 

 may frequently be seen running rapidly on the surface of the 

 ground, with quivering wings and vibrating antennae, and 

 are probably then employed in the search for prey, or some other 

 of the operations connected with providing a store of food for 

 their young. Spiders appear to be their special, if not their only, 

 prey. Several authors have recorded details as to the various 

 ways in which the prey is attacked. Fabre has observed the 

 habits of several species, and we select his account of the modus 

 operandi of species of the genera Pompilus and Calicurgus, in 

 their attacks on poisonous spiders that inhabit holes in the 

 ground or in walls. The wasp goes to the mouth of the spider's 

 burrow, and the latter then dashes to the entry, apparently 



