234 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
with a spine; first submarginal cell longer than second, and as long as third; hind 
tibiae with a sparse pubescence; segments of the abdomen more or less constricted 
at the sutures. 
Small bees, smooth, frequently metallic in coloration (green, blue 
or blue-black) boring in the pith of briars. 
In connection with this and the preceding family and particularly 
for a discussion of Osmia, the student would do well to read Fabre’s 
“Bramble Bees and Others,’’ Dodd, Mead and Co., 1915. 
Ceratina dupla Say, occurs here (see col. plate 3), collected by 
H. L. V. in Rock and Martin counties in September, frequenting asters. 
XY LOCOPIDAE 
Same as Ceratinidae, but with first submarginal cell shorter than second; thorax 
densely pubescent laterally; hind tibiae with two apical spurs; abdomen not elon- 
gate, convex above. 
This group contains many of the largest and most powerful-of the 
bees and is widely distributed. The genus Xvylocopa contains black 
or blue-black species, robust with shiny integument, more or less coy- 
ered with hair. X. virginica is the. large carpenter bee, which bores 
frequently in solid wood, or even, according to Howard, in lumber and 
in joists of buildings. These burrows may be one-half inch in diameter, 
and are sometimes found in beams about porches, sheds, rafters, palings 
of fences, door frames and window sills. 
An interesting statement has been published by Bingham (Brit. 
Ind. Hymenoptera 1, p. 534), according to which X. rufescens Sm. is 
“crepuscular, on fine moonlight nights its loud buzzing can often be 
heard all night long.” Other bees are known to work at night, notably 
Sphecodogastra texana Cress. On July 15 at Prescott, Wisconsin, 
these bees were found working on evening primrose as late as 10 p. m. 
and were not observed upon these or any other flowers in that vicinity 
during the day time. Both males and females of this species have large 
ocelli. (S. Graenicher in Bees of Northern Wisconsin, Vol. 1 Art. 
POE, 
APIDAE 
Apical dorsal abdominal segment of males and females, second recurrent vein, 
depressions of fovae on face, and submarginal cell as in Ceratinidae; tongue very 
elongate, slender and always longer than mentum; apex of sixth dorsal abdominal 
segment in female without a spine; first submarginal cell shorter than second; cheek 
or malar space distinct. Hind tibiae with or without apical spurs, thorax densely 
hairy; three sexes, females (or queens), workers and males. 
These are the true bees, most of them social, and most of them 
storers of honey. Volumes have been written upon the honey bee, 
Apis mellifera L., to which works the reader is referred, for it is mani- 
