1^1 





GROUP 11. PETIOLATA. 

 Parasitic Wasps. 



B. Family Ichneumonidae (Ichneumons). — These 

 wasps can usually be distinguished from chalcids 

 by the following characteristics: (a) larger size; 

 (b) more numerous veins on wings; (c) the an- 

 tennae are not elbowed and have many joints 

 Ichneumons can be distinguished from bracoi 

 (the next group of parasitic wasps we will discuss), 

 by the structure of the wing. Note that the 



second space marked *'cell a" of the posterior or out- 

 er end of the wing (counting from the lower part of 

 the wing), is divided into two smaller cells by a 

 transverse veinlet. (See Plate i6, Fig. 6.) In the 

 wing of braconids this second space or "cell a" is 

 large having no transverse veinlet. (See Plate i6, 

 Fig. 5.) The abdomen and appendages of ichneu- 

 mons are usually more mobile than those of bra- 

 conids. These ichneumons are very useful in- 

 sects, parasitising some insect pests, for example, 

 the acacia moth (Tcia), cut worms such as the 

 larvae of bugong moth, vine moth caterpillars 

 (Phalacnoides) ; they also attack the caterpillar 

 of the emperor gum moth (Antheraea). 



A common ichneumon is the genus Ophiot. 

 (Plate 16, Fig, 8.) It is reddish brown with a 

 rather long petiole to the abdomen. The body is 

 rather thickened and truncate or cut oft abruptly at 



