NOVEMBER, 1905. SOME OBSERVATIONS ON PARASITIC BEES. 
155 
lata Ashm. in the nest of Alcidamea producta Cress, a bee of the 
family Osmiince. 
Sharp, (6), sums up the status of our knowledge of the do- 
ings of the larvae of parasitic bees in the nests of host-bees. He 
says "in such cases the resulting larvae eat and grow more quick- 
ly than the progeny of the host-bee, and so cause it to die of 
starvation. It has been observed that some of these parasitic 
larvae, after eating all the store of food, then devour the larvae 
they have robbed. In other cases it is possible that the first care 
of the parasitic larva, after hatching, is to eat the rival egg." 
A number of observations made during the last 3 years on a 
few species of parasitic bees of our region (representing the 
genera Stelis, Coelioxys, and Triepeolus) bring out several new 
points in this connection. 
STELIS SEXMACULATA ASHM. A PARASITE OF ALCIDAMEA PRO- 
DUCTA CRESS. 
The parasitic bee Stelis S(\rmaculata was described by Ash- 
mead from specimens bred from the nests of Alcidamea producta 
collected by Davidson in the vicinity of Los Angeles, Cal. From 
Davidson's, (7), description of the nest we learn that the Cali- 
fornian Alcidamea producta builds its nest in the stems of the 
elder tree by excavating the broken twigs, and constructing of 
pith and clay the partitions between the cells, as also those near 
the opening of the nest (the "outer defence" as Davidson calls 
them). In our region this bee makes the partitions out of pieces 
of chewed leaves, and never uses clay for this purpose. In this 
variation of habits Alcidamea producta remains true to the 
habits in vogue within the family to which it belongs, since some 
species of Osmia utilize clay, while others resort to vegetable 
matter. On July 20, 1903, I witnessed at Cedar Lake, Washing- 
ton County, Wis., a female Alcidamea producta obtaining her 
leaf material from a wild strawberry, Fragaria virgmiana, sit- 
uated about 3 m. from her nest. The leaves of this plant are 
rather hairy on the under side, and when thoroughly chewed they 
form a felt-like, pliable mass. Alcidamea flies in the surround- 
ings of Milwaukee from the beginning of June to about the mid- 
dle of August, and selects the dry stems of elder, blackberry, 
sumach, and other plants for nesting purposes. 
The bee-bread in the nest of this bee is comparativelv drv, 
4. J. H. Fabre. Loc. cit., p. 117. 
5. C. Verhoeff. Zoolog'ischer Anzeiger, Vol. 15, p. 41. 
