Basilia hispida is the only insect parasite of the flat-headed bats Tylonycteris pachypus and T. robustula in Selangor, Malaysia where this study was conducted between September 1966 and August 1968. The climatic conditions in the laboratory closely approximated to those in the field: seasonal variations in climate were small but diurnal fluctuations occurred. The life cycle of the fly was not affected either by the season or by the sex or species of the host.
A typical life cycle was as follows: adult B. hispida reached sexual maturity within 5 or 6 days of their emergence from the puparium. Copulation largely occurred with newly emerged flies or with females at the time of prepupal deposition; one copulation sufficed for numerous subsequent offspring. The entire larval life of three instars was passed within the female, nourished by maternal secretions. After reaching maturity the female deposited prepupae at 9-day-intervals on the host's roosting quarters, deposition occurring during the day, stimulated by increasing temperature. The length of the pupal stadium depended upon the presence of a host bat; if one was present the pupal period was ca. 25 days. Thus the total life cycle from emergence of the female to the emergence of her first offspring was typically 39 (5 + 9 + 25) days. The sexes were produced in equal numbers. The greater part of postembryonic mortality occurred in the adult instar and was largely due to host-predation. Females were longer lived than males, and it was suggested that they had an average life expectancy of 5–6 weeks in the field.
The life cycle of five other species of Nycteribiidae from two other species of host were briefly examined and no major differences from B. hispida were noted. The results of this and of previous studies indicate that the life cycle is fairly uniform throughout the family.