_Molossus sinaloae sinaloae_, El Recreo, Nicaragua Average 4 ([Male]) 47.6 21.2 18.6 12.3 9.8 7.7 5.4 Minimum 46.7 20.7 18.3 12.0 9.7 7.6 5.3 Maximum 48.6 21.5 18.9 12.6 10.0 7.9 5.5 Average 10 ([Female]) 47.5 20.2 17.8 11.8 9.7 7.3 5.1 Minimum 46.2 20.0 17.6 11.5 9.5 7.1 5.0 Maximum 48.3 20.4 18.0 12.0 9.8 7.5 5.5 -------------------------------------------------------------------- Among females from Departamento de Boaco, none of 18 collected on 20 February was pregnant, whereas three of four obtained on 4 April were gravid (embryos 13, 15, and 17 mm in crown-rump length) as was one (embryo 21 mm) taken on 18 July. Among those from northwest of Diriamba, two of three were pregnant on 30-31 March (embryos 7 and 13 mm in length), whereas only three of eight carried embryos (29, 31, and 34 mm) in mid-August at a time when flying young also were collected. Additionally, a female captured 6 mi WSW Managua on 27 March had an embryo that measured 11 mm. Four adult males collected on 20 February had an average testicular length of 5.7 (4-7) mm, whereas those of seven obtained in late March averaged 5.0 (4-6) mm; testes of two adults taken on 18 July were 6 and 6.5 mm, and those of three taken in the period 12-15 August were 5 mm in length. Molossus sinaloae sinaloae J. A. Allen, 1906 _Specimens._--_Boaco_: Santa Rosa, 17 km N, 15 km E Boaco, 300 m, 1. _Managua_: 1 km N Sabana Grande, 1; 3 mi SW Managua, 1; 8 km SW Managua, 400 m, 3. _Rivas_: San Juan del Sur, 20 m, 1. _Zelaya_: S side Río Mico, El Recreo, 25 m, 73. This mastiff bat can be distinguished easily from the other two large species of _Molossus_ in Nicaragua in that the hairs of the dorsum are relatively long and are pale, frequently white, basally. The species has been reported twice previously from Nicaragua--from Greytown by Miller (1913a:89) and by Goodwin and Greenhall (1964:13), who listed four individuals from Río Grande.