1930 ] 
Hornia minutipennis 
155 
A NOTE ON THE PARASITIC BEETLE, 
HORNIA MINUTIPENNIS RILEY 1 . 
By Phil Rau 
Kirkwood, Mo. 
In the Ecology of a Clay Bank 2 , (p. 236), I have already 
recorded that the parasitic beetle, Hornia minutipennis, was 
twice taken from the nests of the burrowing bee, Antho- 
phora abrupta. Riley has named this species from beetles 
taken from the nests of this bee ( sponsa=abrupta ) collected 
in this region. Since the publication of the ecology paper, 
I have gathered a few meagre notes on the habits of this 
parasite, and since so little is known of its behavior, I beg 
leave to present them here. 
It is well known that the beetle larvae in the triungulin 
stage attach themselves to the pubescence of the bees and 
by this method are transported to the bees’ nests, where 
they feed upon the bee larvae and attain their maturity. 
In 1925, on May 5 and 17, I found one female each time, 
walking about on the lumps of clay containing the nests of 
the Anthophora bees, which I had brought into the labora- 
tory. Some time later, June 7, I found on the surface of 
the clay mass five distinct clusters of triunguli, which appar- 
ently had hatched from eggs which I had not noticed. These 
masses or colonies were separate groups, and the larvae 
did not move about at this stage. However, when I came 
near or brushed them with bits of cotton or dead Antho- 
phora bees, they readily attached themselves to fibers and 
hairs. 
On another occasion a very small hole was discovered in 
one of the bee cells. Upon opening the cell, an adult 
female beetle was discovered inside; hence I assumed that 
the beetle had made the opening. In still another cell, 
where a hole of the same size was found, I removed a dead 
mother beetle and hundreds of living triunguli. Another 
identified by Mr. E. A. Schwarz. 
2Trans. Acad. Sci. St. Louis 25: 236-7, 1926. 
