172 



HYMENOPTERA. 



above, than in the other genera ; the front of the head is about 

 a third longer than broad. The antennae are long and fili- 

 form and sometimes crenulate, as in Figure 91 o, in the 

 [\ males ; the mandibles are stout, broad, sabre-shaped, 

 being much curved, with low flattened teeth, and the 

 maxillary palpi are longer than the labial palpi. The 

 wino-s are rather broad, with the three subcostal cells 

 Ivino- in a straight row. The abdomen is slightly com- 



J & 



pressed, and equals in length the remainder of the 

 body. The sting is very large and formidable, and ex- 

 cessively painful, benumbing the parts it enters. They 



Fijr !l1 a - are exceedingly active, running and flying over sandy 



places like winged spiders. 



There are about five hundred species of this genus described. 



They are usually shining black or deep bluish black, with 



Fig. 92. 



smoky or reddish wings, and sometimes a reddish abdominal 

 band. This genus is interesting, as affording in its form a 

 mean between the globular thorax and short body of the 

 Apt ((riff and the elongated body of the Iclineumonidtv. 



The Pompilus formosus Say (Fig. 92), called in Texas the 

 Tarantula-killer, attacks that immense spider the Mygale Hentzii, 

 and. according to Dr. (1. Lincecum (American Naturalist, May, 



