232 SEVENTEENTH Report STATE ENTOMOLOGIST oF MINNESOTA—1918 
In Europe Colletes is parasitized by Miltogramma punctata, a 
tachinid fly, which lays its own egg in the cell on the food intended for 
the Colletes larva. Another parasite of this genus is the cuckoo-bee, 
Epeolus variegatus. 
We figure Colletes compactus Cress., and C. americanus Cress. 
from Minnesota specimens. The first named has been collected from 
flowers of Solidago and asters. Colletes sp. has been taken in Hub- 
bard, St. Louis and Itasca counties in August. 
SPELIDIDAE 
Females and males as in Hylaeidae but second recurrent vein never strongly 
bent or directed outward before joining first portion of subdiscoidal vein; tongue 
filiform; no depressions or fo. ae on face. Wings with two submarginal cells; claws 
left, inner tooth subapical. 
These are bees with whitish 
margins on the dorsal segments 
of the abdomen. Females of 
the genus Stelis, the only genus 
in the family, lay eggs in Os- 
mia’s cells in blackberry stems, 
before the rightful owners have 
oviposited. Thus the egg of 
Stelis is lower down in the mass 
of food than is the later laid 
of Osmia. The larva of 
2 FO 
eg 
oOo 
Stelis grows more rapidly than 
the Osmia larva and eats the 
latter. 
Stelis also preys upon a mason bee, Chalicodoma. Stelis (Chel- 
yina) nitidis Cress. (see drawing), is a Minnesota species. 
Fig. 125. Stelis (Chelynia) nitidus Cress. 
MEGACHILIDAE 
Same as Stelididae but claws simple or in some species with a basal tooth; labrum 
entirely covered by the clypeus; hind tibiae with two apical spurs. 
This family contains the leaf-cutting bees and their parasites, as 
well as the mason bees. The latter earn their name by constructing 
small earthen cells in various situations. 
The leaf-cutting bee, Megachile, is the insect which cuts semi- 
circular pieces from the edges of rose leaves, and from other tender 
leaves. These pieces of green leaves are used to line the tunnel which 
