Beewolf
Beewolves (genus Philanthus), also known as bee-hunters or bee-killer wasps, are solitary, predatory wasps, most of which prey on bees, hence their common name. The adult females dig tunnels in the ground for nesting, while the territorial males mark twigs and other objects with pheromones to claim the territory from competing males.
Charles Robertson (entomologist)
Charles Robertson carried out what is still the single most intensive study of flower-visiting insects of a single locality, culminating in a 221-page book published in 1928 under the title Flowers and Insects. From among the specimens he collected in the process of doing this study, he named over 100 new species of bees and wasps. Scientists in 1970–1972 did a similar survey, and found that most of the bees noted by Robertson were still present. This is presumably due to the existence of bee habitat in hedgerows, on slopes, and in other non-agricultural land in the survey area. The rare bee "Andrena lauracea" is known only from these two surveys (one bee specimen each) and from two specimens from Texas. Biologists from Washington University in St Louis are currently studying changes in pollinator activity by comparing these older data sets to new data. Study was published in Science, February 2013, Plant-Pollinator Interactions over 120 Years: Loss of Species, Co-Occurrence and Function by Laura A. Burkle1, John C. Marlin, Tiffany M. Knight.[5]