NORTH AMERICAN GEOTRUPINAE — ^HOWDEN 173 



posterior third. In females, the only black pronotal markings may 

 be medial pronotal spot behind the transverse carina, or in some 

 cases the spot is produced into a broad band running the length of 

 the pronotum; otherwise markings are similar to male. Ventral 

 portions of thorax and abdomen brownish yellow. Tibia reddish 

 brown to black. Vertex and clypeus densely, coarsely, irregularly 

 punctured, least in posterior portion of vertex, more so on clypeus. 

 Pronotum coarsely, irregularly punctate medially, lateral portions 

 more finely, closely punctured, more so anteriorly. Minute secondary 

 punctures evenly distributed over pronotum. Declivity of pronotal 

 modification coarsely punctured mainly in lower half, but with a few 

 punctures scattered over entire face in some cases. Scutellum with 

 vague, median indentation running its length and with minute 

 secondary punctures. All elytral striae well developed except basal 

 portion of eighth. Poorly delimited punctures usually separated by 

 slightly less than own diameter, closer together than in farctum. 

 Elytron without setae, except epipleuron and elytral margin each 

 bearing a row of long setae. Foretibia armed with seven or eight 

 teeth on outer margin. Mesosternal prominence in front of middle 

 coxae well developed, only slightly concave on anterior face, elevated 

 above mesosternal plane. 



Head of males with tubercles moderate, horn well developed, not 

 generally bifid at tip. In male, pronotal modification well developed; 

 pronounced transverse carina moderately emarginate, scarcely wider 

 than upper portion of lateral limiting groove, much narrower than in B. 

 bruneri. Lateral carinae and limiting grooves well developed. In 

 female transverse carina small and evenly arcuate, lateral carinae and 

 limiting grooves obsolete. 



Genital capsule of male (pi. 3, fig. 1) moderately elongate, not 

 lobate basally, tip of lateral lobe rounded, not prolonged as in B. 

 farctum, similar to B. bruneri. 



One of the most variable species of Bolbocerosoma in extent of the 

 black markings, it is still easily distinguished by the median black 

 pronotal spot or stripe, the well developed elytral striae, and usually 

 by the postmedian black spot confluent with elytral margin, but not 

 with sutural interval. 



Bolbocerosoma tumefactumy the most common northeastern species, 

 is particularly abundant in some areas of New Jersey, Maryland, and 

 Pennsylvania, where on occasion it has been found biu-rowing in golf 

 com-ses to such an extent that it was considered a pest. 



The species is active from May until October, with the majority of 

 specimens being collected in July and August. A few specimens were 

 collected at light, indicating some nocturnal surface activity. Sim 

 (1930, pp. 139-147) mentioned collecting many specimens near 



