8 WHEELER— THE PARASITIC ACULEATA. 



Graenicher found the behavior of the female Tricpcohis, Ca:lioxys 

 and Stelis to be very similar to that of Argyrosclcnis. 



There is one genus of bees, Sphecodcs, which must be briefly 

 considered, because it has been the center of a prolonged contro- 

 versy. These insects are fairly common in Europe and North Amer- 

 ica and closely resemble the species of Halictus except in color, as 

 they have the abdomen wholly or in part vivid red and in the hind 

 tibiae which are very sparsely pilose and therefore suggest a degen- 

 erate condition of the pollen-collecting apparatus. More than a 

 century ago de Walkenaer (1817) maintained that Sphecodcs is a 

 parasite of Halictus, and the same view was more or less emphat- 

 ically maintained by Wesmael (1835), Lepeletier (1841) Spinola 

 (1851), and Taschenberg (1866), but Fred. Smith (1851) and 

 Sichel (1865) held that it nests independently. The controversy 

 continued, however. Perkins (1887, 1889) believed that Sphecodcs 

 might be occasionally parasitic and Friese and von Buttel-Reepen 

 (1903) regarded it as perhaps incipiently parasitic. Rudow (1902) 

 repeated the old statement that it nests independently. Marchal 

 (1890, 1894) and Ferton (1890, 1898) witnessed some serious com- 

 bats between Sphecodcs and the Halictl, whose nests it was trying 

 to enter. Ferton (1905) saw a Sphecodcs suhquadratus breaking 

 into the nest of Halictus malachurus. 



" Not being able to seize bj^ the head the sentinel bee which barred her 

 passage, she tunneled towards the Halictus burrow and succeeded thus in 

 seizing and kilHng the guardian, which she tossed backward out of the bur- 

 row. A second and a third Halictus that rose in the burrow in succession to 

 replace the first, met the same fate." 



Morice (1901) contended that such aggressive behavior showed 

 that the Halictus was not a parasite, because some parasitic bees, 

 e. g., Notnada, seem to entertain friendly relations with their hosts. 

 Three investigators, however, have succeeded in breeding Sphe- 

 codcs from Halictus and Andrcna nests. Breitenbach (1878) long 

 ago took S. rubicundus from the brood-cells of Halictus 4-cinctus 

 and Sladen (1895) found pupae of the same species in the nests of 

 Andrcna nigroccnca and labialis. Finally Nielsen (1903) gave co- 

 gent reasons for regarding S. gibhus as a parasite of Halictus 

 4-cinctus. He says : 



