Table 1

Table 1. Number of bee species and collected at Carlinville, Illinois, USA, during 1884–1916 by C. Robertson, and during 1970–1972 by W. E. LaBerge and J. C. Marlin. This analysis excludes Apis melifera, Bombus spp., and parasitic bees.

	Total no. spp. in both studies	No. spp. 1884–1916	No. spp. 1970– 1972	No. spp. unique to 1884– 1916	No. spp. unique to 1970–1972	Robertson spp. re- collected (%)	Jaccard similarity index**	Sorensen similarity index**
Total no. bee spp. collected	228	214	154	74	14	65%	0.614	0.761
No. bee spp. on 24 selected plant species*	179	157	150	29	22	82%	0.715	0.883

* The present authors concentrated their collecting on 24 plant species on which Robertson found a relatively large number of species. Robertson collected on over 400 plant species.

**These indices are commonly used to measure the similarity of species in samples where the data include presence or absence. The indices equal one if similarity is complete, and zero if the sites or samples have no species in common.