BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 24I 



seven female parasites from oothecae of Blattella germanica. He 

 placed female parasites witli adults of B. germanica in a glass cage. As 

 soon as oothecae could be seen between folds of a woolen rag, he re- 

 moved all the larger cockroaches and held the oothecae until the para- 

 sites emerged. Fahringer may have been dealing with a different 

 species of cockroach, because placing oothecae in crevices (or between 

 folds of rag) is a habit foreign to B. germanica, the female of which 

 usually carries her ootheca until hatching or until about a day before. 

 Edmunds (1953b) could not induce this wasp to parasitize eggs of B. 

 germanica. ] 



Periplancta americana, Istrian Peninsula (Fahringer, 1922) ; Pal- 

 estine (Bodenheimer, 1930) ; U.S.A., Ohio (Edmunds, 1952, 1953b, 



1954)- 



Adult behavior. — The wasps (pi. 33, A) are very active; they walk 

 about a great deal and fly short distances. They are often found in 

 abundance in buildings infested with the larger domiciliary cockroaches 

 where they may reproduce for many generations without leaving the 

 premises. Specimens have also been collected outdoors. (Edmunds, 

 1953, 1954.) As the adult walks about, the laterally compressed abdo- 

 men moves up and down like a waving flag ; because of this behavior, 

 these insects are commonly known as ensign-flies. Cros (1942) main- 

 tained adults 17 days without food. Edmunds (1954) fed adults on 

 unidentified flowers in the laboratory. He also maintained them for 20 

 days after capture on a 5-percent honey solution. 



Oviposition. — A female P. punctata selected oothecae of P. ameri- 

 cana for oviposition and ignored those of B. orientalis and Parcoblatta 

 pensylvanica in the same cage. Oviposition was accomplished as de- 

 scribed for Evania appendigaster. One ootheca was turned over onto 

 its right side by the wasp before she oviposited. (Edmunds, 1952.) 

 Although there seemed to be a "preferred" position for oviposition, it 

 was not obligatory. The usual position was for the female to face the 

 keel of the ootheca, but she also oviposited from the opposite side or, 

 rarely, directly down into the side of the ootheca. The average time 

 spent by females in 10 ovipositions was 29 minutes (range 16-62 

 minutes) . The wasp apparently could not determine whether the eggs 

 had been previously parasitized. The wasp laid her egg between the 

 cockroach eggs rather than in them and she oviposited into oothecae 

 that had just been dropped and those two weeks old or older. On 

 three occasions nymphal cockroaches emerged within a few hours 

 after the wasp had oviposited. (Edmunds, 1954.) Apparently, for 

 successful parasitization the wasp must oviposit before the cock- 

 roaches have reached the final stages of preemergence development. 



