THE GENETICS OF HABROBRACON JUGLANDIS ASHMEAD 



tend to cling to the sides of the vial and must 

 be brushed off into the nev; vial. Transfer at 

 three day intervals is continued until the fe- 

 male dies. 



The larval stage lasts about two days, at 

 the end of which time the larvae spin cocoons* 

 with silk from the salivary glands. The cocoon 

 entirely surrounds the larva, but only a very 

 thin layer of threads is laid down where it ad- 

 heres to the inner surface of the vial; thus it^ 

 is possible to watch the development of the 

 pupa from this side. The caterpillars by this* 

 time are reduced to shrivelled remnants which 

 may be removed from the vials. 



In the higher hymenopterans the end of the 

 stomach is closed during larval life. The fecal 

 matter is, therefore, retained in the stomach 

 until pupation and then discharged into the end 

 of the pupal case. This discharge appears as a 

 dark brovm mass and marks the posterior end of 

 the developing pupa. 



After two days, the pupa changes externally 

 *from the worm form of the larva into approxi- 

 mately adult insect form. Legs and wings are 

 not fully formed until the third day of pupal 

 existence when pigmentation and sclerotization 

 take place rapidly. Compound eyes are formed 

 externally by the end of the second day, but 

 the internal tissues are not completely devel- 

 oped until the third day, and facets are not 

 apparent until the wasp is almost ready to^ 

 hatch. Near the end of pupal life the thorax 

 and antennae become deeply pigmented. The time 

 of pupal life varies somewhat, but most wasps 

 average about four days. 



In three day pupae, the ventral side lies^ 



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