Chapter II 

 DESCRIPTION 



Habrobracon juglandis in the adult stage is 

 approximately three millimeters in length. Var- 

 iations in size are directly related to the 

 quantity of food available to the larvae. Gen- 

 eral body coloration varies from honey-yellow 

 to jet black, depending largely upon the tem- 

 perature during development. Females are, in 

 general, less deeply pigmented than males in 

 any given strain. Body colors are similar on 

 dorsal and ventral sides of head and thorax. 

 The distribution and quantity of integumental 

 pigmentation are exceedingly variable, but nor- 

 mally produced individuals are bilaterally sym- 

 metrical. The color pattern of the praescutum, 

 scutum, mesoscutellum, and the dorsal plate of 

 the mesophragma is used in classifying degrees^ 

 of pigmentation since it is consistently re- 

 lated to muscle areas and is not complicated by 

 other factors. There is a high degree of asym- 

 metry of pigmentation in specimens mosaic for 

 mutant factors and for sex. As compared with 

 females (Fig. 1), males (Fig. 2) have longer 

 antennae. The antennae consist of a scape, and 

 a pedicel, in the males a flagellum of 20 to 22 

 segments, and in the females a flagellum of 13 

 to 15 segments. The males have larger ocelli, 

 smaller wings and legs, and larger compound 



