112 
The Bulletin 
rare. In pulling up a stalk of corn in a field wliicli had been planted 
in early July, I discovered a larval Tabanid firmly anchored to a larva 
of a corn bill bug of large size which was evidently nearly ready to 
pupate. It took considerable force to dislodge the Tabanid larva, 
which was placed in a tight tin box with four other good-sized corn 
bill bug larvae and two pupae. After a few minutes the box was exam¬ 
ined and the Tabanid larva had again attached itself by its mouth- 
parts to one of the corn bill hug larva. The box was placed together 
with some other boxes and brought back to the laboratory, where op¬ 
portunity was not offered for an examination until the following day. 
By this time the Tabanid larva had died, although it had completely 
eaten the four larvae and one of the pupae with the exception of the 
hard outer chiten and had eaten a hole into the side of the other pupa, 
On the face of this observation it would look as if Tabanid larvae 
might be very important enemies of Sphenophorus larvae and pupae, 
especially those that are exposed in the ground among the roots of the 
corn plant, for the predaceous habits of Tabanids are well known and 
they both occupy the same sort of situations generally, i. e., moist, 
swampy situations, and must, therefore, he thrown constantly in con¬ 
tact. However, this single observation is the only evidence we have 
bearing on this point, and we have examined hundreds of larvae and 
pupae in the fields both in cyperus swamps where the natural conditions 
for the Tabanid larvae would he good and in corn-fields where the 
natural conditions would not be so good. The same day the above 
observations were made we spent much time searching for other 
Tabanid larvae, but none were found either in the field where corn bill 
bug larvae abounded or along the ditch banks under very favorable 
conditions for Tabanid larvae. 
Mr. Smith was much troubled in his investigations by a small mite 
which invaded the insectary. Of these mites he makes the following 
statement (Smith, 1913) : 
“Mites have proved to be a pest of both the larvae and the pupae in 
confinement; but field observations do not show that the same thing 
is true under perfectly normal conditions. During the breeding work 
many larvae are apparently killed, or worried so as to prevent regular 
growth, by a small mite identified by Mr. Banks as Tyroglyphus ameri- 
canus Bks. These mites were often found on the bodies, or in their 
feeding channels, and usually such larvae did not grow well. Very 
young larvae were sometimes killed by the mites.” 
During 1913 the insectary was moved and we have had no further 
trouble with this mite. Neither has the mite ever been observed in 
the field in the natural burrows. 
A good deal of trouble has been experienced in our breeding work 
with both larvae and pupae, which had apparently died from attack 
of some fungous growth. However, such larvae were usually found in 
stalks of corn that were badly decayed or molded, and the chances are 
