_Number of parasites per oötheca._--In _Eurycotis floridana_: In the laboratory, 3 oöthecae that had been exposed to 20 female wasps yielded an average of 648 parasites (range 606 [from original data] to 685) (Roth and Willis, 1954b). In _Neostylopyga rhombifolia_: One oötheca yielded 73 parasites (Pemberton, 1941). In _Parcoblatta_ sp.: Two oöthecae yielded an average of 100 parasites (Edmunds, 1953a). In _Periplaneta americana_: 100 parasites per oötheca (Seín, 1923); 140 (Schmidt, 1937); 25 (Rau, 1940a); 7-38, average 33 (Usman, 1949); 71 (Wolcott, 1951); 4 oöthecae exposed to 20 female wasps yielded an average of 204 wasps (range 164 [from original data] to 261) (Roth and Willis, 1954b); average of 30-40 (Cameron, 1955); 39 oöthecae yielded an average of 93 parasites (range 12-187) (Edmunds, 1955). In _Periplaneta australasiae_: Oöthecae yielded an average of 40-50 adult parasites (Cameron, 1955); about 50 (Shaw, 1925). _Sex ratio._--3 [F][F]:1 [M] (Usman, 1949); 4 [F][F]:1 [M] (Cameron, 1955); 2-8 [F][F]:1 [M] (Roth and Willis, 1954b); 1.2 [F][F]:1 [M] (Edmunds, 1955). Parthenogenesis exists; the unfertilized eggs produced only males (Roth and Willis, 1954b; Edmunds, 1955). _Distribution._--Probably worldwide. Eastern and southern U.S.A.; Central and South America; Europe; Arabia; Africa; India; Formosa; Hawaii. =Tetrastichus periplanetae= Crawford _Natural hosts._--_Periplaneta americana_, Mozambique (Crawford, 1910); Union of South Africa (parasites reared from oöthecae collected in Durban, Natal, by the City Health Department): The parasites were identified by Burks (personal communication, 1956). Jamaica (Gowdey, 1925); Réunion Island (Bordage, 1913). "Domestic cockroach," Puerto Rico (Wolcott, 1951). =Tetrastichus= sp. I _Taxonomy._--Burks (personal communication, 1956) stated that this species (specimens of which are in the U.S. National Museum) is very close to _T. hagenowii_. _Natural hosts._--_Periplaneta americana_, Union of South Africa (parasites reared from oöthecae collected in Durban, Natal, by the City Health Department [Burks, p. c., 1956]). _Periplaneta australasiae_, Manila, Philippine Islands (Burks, p. c., 1956). =Tetrastichus= sp. II _Synonymy._--Because of the war, Cros (1942) could not determine this insect specifically. He designated it provisionally and with reserve under the name _Eulophus_ sp. However, Burks (p. c., 1956) stated that the species is most certainly a _Tetrastichus_ from the description given; but, it is apparently not _T. hagenowii_ because of its brilliant steel-blue color.