103 
riage, and are probably neither parasitic nor predaceous. When a 
suitable breeding ground is reached the mites drop and transform, and 
begin to feed on bacterial and fungous growths. 
Parasites of the beetle 
Ortatip Fires 
(PyrcoTa UNDATA WIED. and P. vatipa Harris) 
Our earliest record of P. undata as a parasite of Phyllophaga adults 
was made by Prof. F. M. Webster, who reared it in the spring of 1891 
from beetles collected at Lafayette, Ind., and the first published record 
is that of Dr. Forbes in 1907 (26). P. valida was first reared and se- 
corded by the writer in 1913 (15), and we have since reared it many 
times. 
The life histories of the two species are substantially alike. The 
beetles are attacked only at night while they are feeding, or in flight, 
the Pyrgota fly alighting on the back of the beetle, which if feeding is 
Fic. 30. Pyrgota undata Wied., female. 
usually sufficiently disturbed to cause it to drop, at the same time spread- 
ing its wings to break the fall. The fly immediately takes advantage 
of this act to thrust its ovipositor through the exposed thin abdominal 
wall beneath the wing covers and to lay an egg in the abdomen. The 
abdomen and ovipositor of Pyrgota are admirably adapted to this act, 
the former being curved, with the tip hard and conical, and the oviposi- 
tor being a fleshy muscular organ of medium length with a sharp-pointed 
chitinous tip (Fig. 31). 
