The effect of fruit species on parasitization ofAnastrepha ludens(Loew) byDiachasmimorpha longicaudata(Ashmead) was studied. The roles of fermenting fruit volatiles, size, and color in host habitat selection by this parasitoid also were investigated. The lowest percentage parasitism was recorded for larvae in grapefruit,Citrus paradisiMacf. On the other hand, grapefruit volatiles and size proved most attractive toD. longicaudata. Greater percentage parasitism was recorded for larvae in smaller and apparently less attractive fruit. The length of the parasitoid's ovipositor, depth of the fruit pulp, and host larval behavior could explain these contrasting results. Citrus volatiles attracted almost twice as many female parasitoids as volatiles of mango,Mangifera indicaL., or peach,Prunus persicaL. Fruit>5 cm in diameter were equally attractive toD. longicaudata. Selection of colors byD. longicaudatawas not statistically different among colors tested.