CHRYSIDID.E. PRJEDONES. *1G5 



sitic insects. Lastly, the CHRYSIDIDJE, or Ruby-tailed Flies, 

 constitute a small group, distinguished by having the abdomen 

 composed of only from three to five segments, the remainder 

 being formed into a tubular apparatus, capable of being drawn 

 together, or extended like a telescope, and having a minute sting 

 or ovipositor at its extremity. These insects, although but of 

 small or moderate size, are amongst the most splendid of our 

 native species ; being adorned with brilliant metallic tints, 

 usually blue and green on the head and thorax, and a fiery 

 copper-colour or ruby on the abdomen ; hence they have been 

 termed the humming-birds amongst insects. They may be 

 observed during the hottest sunshine, flying and running with 

 great vivacity over walls, palings, sand-banks, and occasionally 

 upon flowers (especially those of the Umbelliferse) and leaves. 

 The females do not insert their eggs in the bodies of other insects 

 or their larvae, but take an opportunity of depositing them in the 

 nests of the different Wild-Bees and other Hymenoptera, during 

 the period when the latter are provisioning their nests for the 

 support of their own progeny ; which is thus starved by the 

 intruder, whose voracity is such as to require the whole supply 

 of food that had been prepared for the legitimate occupiers of the 

 nest. In this habit these insects closely resemble the Cuckoo 

 ( 351). In many points of structure, the Chrysididae bear a 

 strong resemblance to the Aculeate Hymenoptera ; and they may 

 be considered as intermediate between the two great divisions of 

 the Order. 



758. Section III. ACULEATA PRJEDONES. The Hymenoptera 

 of the Aculeate division, like those of the second section of the 

 Terebrantia, have the abdomen connected with the thorax by 

 means of a peduncle or foot-stalk, which is often (as in the 

 Wasp) extremely slender. The Predaceous subdivision of this 

 group contains several families ; of which the most important 

 only will be noticed in detail. 



759. The CRABRONID^K, LARRID^E, BEMBECIDJE, SPHEGID^E, 

 SCOLIID^E, and ^IUTIL' ID^E, may all be considered under one 

 general description ; they form a group, which may be termed, 

 from their peculiar habits, that of Fossores, or Diggers ; and 



