SOME FACTS ABOUT WASPS AND BEES. 323 



interesting habits have been closely studied by a number of 

 naturalists. Mason bees of the genus Osmia are also small and 

 brilliantly colored, blue or green, having habits somewhat akin 

 to those of Megachile. A European species is said to build her 

 cells of mud, depositing them in the empty shells of snails. Many 

 other species of this genus Osmia, in various parts of the world, 

 possess habits full of interest to us, that have been described in 

 the books with greater or less detail. Then we have the less 

 intelligent types of those bees that burrow in the ground, that 

 are solitary, and leave their young to look out for themselves. 

 These fossorial bees see their types in such forms or species as 

 the common Andrena vicina, that I have observed in many parts 

 of New England. Parasitic bees, called cuckoo bees (as Nomada 

 sex-fasciata) , prey upon these fossorial forms, such as Andrena or 

 its allies of the genus Halictus and others, by laying their eggs 

 in their nests. They are also infested by numerous other para- 

 sites, such as by certain ichneumon flies and oil beetles (Heloe)> 

 and others. Some of the South American bees are destitute of 

 stings (Melipoma, Trigona), and I have frequently seen a large bee 

 here near Washington that does not sting. It has the appearance 

 of a Bombus, but the fore part of the head is nearly all of a very 

 pale yellow, almost white. 



Carder bees (Bombi muscorum) are known to all frequenters of 

 open fields and meadows, after the haying season has commenced. 

 A popular writer at hand says : " They select for their nest a shal- 

 low excavation in the ground about a foot in diameter, or, if such 

 a one is not to be found, they make one with prodigious labor. 

 This they cover over with a dome of moss, or sometimes with 

 withered grass. They collect their materials by pushing them 

 along upon the ground, working backward like the tumblebugs. 

 Frequently in the spring a single female founds a colony, and by 

 perseverance collects the mossy covering in the way described ; 

 later in the season, when the hive is populous and can afford more 

 hands, there is an ingenious division of this labor. A file of bees, 

 to the number sometimes of half a dozen, is established from the 

 nest to the moss or grass which they intend to use, the heads of 

 all the file of bees being turned from the nest and toward the 

 material. The last bee of the file lays hold of some of the moss 

 with her mandibles, disentangles it from the rest, and, having 

 carded it with her fore legs into a sort of felt or small bundle, she 

 pushes it under her body to the next bee, who passes it in the 

 same manner to the next, and so on till it is brought to the border 

 of the nest in the same way as we sometimes see sugar loaves 

 conveyed from a cart to a warehouse by a file of porters throwing 

 them from one to another. The elevation of the dome, which is 

 all built from the interior, is from four to six inches above the 



