276 



The Orders of Insects 



In all the following 

 families of Hymen- 

 optera the trochanters 

 are undivided. 



Chry sididae. — 



The Chrysididce are a 

 comparatively small 

 fa m i ly of Hymen- 

 optera distinguished 

 by the brilliant blue, 

 green, or crimson 

 metallic hues of their 

 exceedingly hard and 

 firm exo s k e le t o n. 

 The hind-body has 

 only three to five 

 visible segments. 

 The thirteen- 

 segmented feelers are 

 elbowed. The 

 females lay their eggs 

 in the nests of bees 

 and wasps, where the 

 chrysid larva; live as 

 cuckoo- parasites, 

 devouring the food 

 stored for the bee or 

 wasp-grubs. Several 

 hundred species are 

 known and the 

 family is generally 

 distributed. 



Formicidae. — The 



Formhida or Ants are 

 a large and highly 

 important family of 

 Hymenoptera. They 

 are characterised by 

 the great constriction 



„, . ... ,r.,ofthe "stalk" or 



Fig. 153. — Ant, JetraDioriuin co'spitum (Linn.), , , , . • 



Europe, a. Female ; <^. female after loss of wings ; secona abdommal 

 c. male; rf. "worker" ; ^. larva; ^. pupa, magni- segment at its front 

 fied 4 times ; f. head of larva, more highly magni- and hind edges, SO 

 fied. From Marlatt, Bull. 4 (n.s.), Div. Ent. ^j^^^ ;j assumes a 

 U.S. Dept. Agr. , , , , 



sw^ollen or nodular 



form centrally ; in many genera the third abdominal segment forms 

 part of the " stalk " and is similarly nodular. The fourth segment is 



