Their larvae feed on glandular secretions and develop within the female's oviduct, often for long periods.
ðɛɹ lˈɑːɹviː fˈiːd ˌɔn ɡlˈændʒuːlɚ sᵻkɹˈiːʃənz ænd dɪvˈɛləp wɪðˌɪn ðə fˈiːmeɪlz ˈoʊvɪdˌʌkt, ˈɔfən fɔːɹ lˈɔŋ pˈiəɹɪədz.