586 Mr. D. Sharp and Mr. F. Muir on the Comparative 



faces. Basal-piece large and curved, situated on ventral (?) side. 

 Internal sac large and complex; surface covered with very short 

 spines with a patch of dark hairs towards the base. 



A. simplicollis is very like A. laticollis but the sac bears 

 a large curved chitinous plate near base, a patch of spine- 

 like hairs about the middle and another near the apex, 

 the rest of the surface covered with short spines. 



In Cloeot'us, Millcngcnia, Anaides, Li])arochnts, ITyhosorus, 

 and Geotrupcs the lateral lobes are free, or only connected 

 together at their bases. In Aj^hodius the lateral lobes 

 have membranous extension along their edges but they 

 are not amalgamated together. In the Coprinae the 

 lateral lobes are connected together by membranes and 

 form a more or less complete tube which includes the 

 median lobe. 



Phacochrous cmarginatiLs{\) (PJ. XLV figs. 16 and 16a). 



Median lobe small but well chitinised ; median orifice on ventral 

 side of tip ; median foramen large and basally placed. Lateral lobes 

 asymmetrical, the right shorter and broader than the other, concave on 

 inner side at base for the reception of the median lobe ; left curved, 

 with projection near base on dorsal edge. Basal-piece large, form- 

 ing a chitinous tube with a large opening on the ventro-basal part. 

 Internal sac small and simple, covered with brown hair. When at 

 rest the aedeagus lies on its side. 



Typhocus typhoeus (PI. XLV figs. 17 and 17a). 



Median lobe reduced to a small chitin ring {ml) projecting into the 

 basal-piece as two median struts (ms). Lateral lobes small, but 

 entirely concealing the median lobe. Basal-piece large, forming 

 a chitinous lobe, bent downward near the base, the basal opening 

 large, somewhat dorsal and the edges asymmetrical ; the apical 

 ventral margin (o) is j^roduced beyond, and conceals, the base of 

 the lateral lobes. Internal sac small, covered with brown hairs. 



Geotrupes pyrenaeua, var. from Reynosa ; is of the same type as 

 Typhoeus but the ventral apical margin is produced as two broad 

 plates which cover the ventral side of the lateral lobes. 



In 0. stercorarius, also the ventral distal edge of the basal-piece is 

 produced into two spatulate lobes which cover the ventral side of 

 the lateral lobe and the dorsal edge is produced into two broad lobes 

 which cover the dorsal surface of the lateral lobes. The lateral 

 lobes are small and asymmetrical. The median lobe is reduced to a 

 membrane supported by the median struts consolidated into one 



