Very little has been written on female delinquent gangs or the relationship of girls to male gangs, but a few papers have noted that girls can only achieve a position in the gang world through social relationships with gang boys and behavior that was approved by them. As part of a research project on juvenile gangs, 207 gang and nongang black youths who had been detained in Los Angeles county Juvenile Hall were interviewed in 1964 about their delinquent acts and female participation. Out of the 182 delinquent acts for which complete data are available, only 4 had been partially planned by girls and those involved only nongang boys. analysis of the responses showed that females participated in 14.5 percent of the delinquent incidents and played a secondary role, such as holding weapons or observing, in 9.1 percent. The degree of female exclusion was greatest among boys 10-through 14-years old. Girls were most likely to participate in violent crimes and miscellaneous minor incidents and least likely to engage in burglaries and property crimes. Many violent incidents, however, were undertaken for self-protection. According to the survey, 26.2 percent of the incidents would have been postponed and 41.8 percent cancelled if girls happened on the scene just before the act occurred. The preventive effect was greater for older boys and nongang members. This finding disproves an earlier theory of social scientists that females instigate males to commit criminal acts. Although contemporary researchers need to update the Los Angeles data, this analysis suggests that young women in central city neighborhoods are excluded from illegitimate opportunities as well as legitimate ones. Statistical tables and a bibliography of 13 references are included. (Author abstract modified)