224 NEW YORK STATE MUSEUM 
Oligarces ulmi Felt 
1911 Felt, E. P. Econ, Ent. Jour., 4:477-78 
The larvae of this species were found at Nassau, N. Y., March 
18, 1911 in the thick, partly decaying bark of an old elm, Ulmus, 
cut some two or three years ago. They were so inconspicuous and 
concealed in the tissues that there was some doubt for a time as to 
there being anything living in the bark, though one or two exuviae 
led us to believe that larvae might be present. The infested bark 
was brought into a warm room March 2oth and on the 22d a num- 
ber of whitish transparent young appeared. By the 27th there were | 
literally thousands upon the inside of the breeding jars, crawling 
freely upon the glass. Many perished while others doubtless re- 
established themselves in the bark. These larvae do not appear very 
amenable to laboratory methods, since we were unable to obtain — 
adults from a small piece of bark containing hundreds of larvae — 
clamped to a microscopic slide and kept in a small box. The few © 
placed in water under a cover-glass soon escaped. 
The first pupa was observed April 18. When discovered it was 
standing at an oblique angle, being supported, by the presumably 
glutinous posterior extremity, since at this stage there are no clasp- 
ing organs. The pupa soon turned and twisted, released its hold 
and was shortly lying at a totally different angle upon the moist 
surface of the wood. The pupal period probably extends over two 
or three days. The pupae evidently work themselves partly out of 
the wood before disclosing the adult. The first imagoes were found 
April 24th, females occurring in increasing numbers until about 
the 26th, at which time males became very numerous and continued 
so to the 29th. The adult flies emerge almost entirely between Io 
a.m. and noon. They display a marked preference for the light, 
crawl freely, and when abundant run about in much the same man- 
ner as a swarm of winged ants. They crawl easily upon the sur- 
face of a glass cage though they frequently drop. Very little can 
be seen of the midges except at the hours above named, even when 
they are allowed to remain in the cage from day to day. It is prob- 
able that the eggs are deposited shortly after the females emerge. 
An individual may contain one to four ova, each with a length about 
three-fourths that of the abdomen. One female dropped in alcohol 
extruded two eggs which remained attached to the extremity of the 
abdomen (plate 14, figure 4). 
