80 
more or less indistinct longitudinal black streaks; the abdomen, black 
with the anterior margin of each segment banded with grayish 
bloom, giving the appearance of alternate bands of gray and white; the 
entire body, including the head, set with conspicuous long hairs or 
bristles; and the transparent wings tinged with brown at the base and 
the wing veins faintly margined with brown. The flies are to be found 
from May till September, most often in June or July, occasionally at 
lights, and frequently on the ground in fields, especially corn fields. They 
are exceedingly alert and difficult to capture, although they will remain 
quiet and apparently unsuspecting until one approaches quite near, and 
when disturbed they usually light only a few feet ahead. Pairs have 
been observed in copula on the ground in corn fields in June and July. 
The female oviposits in the ground, probably in cracks, and the larva 
enters the grub, but just how this is effected has not been determined. 
Our observations show that oviposition occurs in fields either cultivated 
or in grass, probably more frequently in the former although our records 
are conflicting on this point. The small maggots remain within the 
grub until mature, passing the winter therein and completing their 
Fic. 15. Microphthalma disjuncta Wied., puparium: anal end, 
and one posterior spiracle. 
growth the following spring. The infested grub feeds and acts normally 
until within a day or two of its death, which would indicate that the 
maggots feed entirely on the fatty tissues at first, not attacking the . 
vital organs until nearly full-grown. The first indication of the pres- 
ence of these parasites is the death of the grub and the coincident 
appearance of the anal end of the maggot through the skin of the grub, 
the conspicuous posterior spiracles showing prominently (Pi. VI, Fig. 
18). About the same time the grub begins to liquefy (Pl. VI, Fig. 20), 
apparently melting away, and frequently the parasitic larva pupates 
within 24 hours from the time it is first noticed (Pl. VI, Fig. 19, 24). 
Maggots were observed, in grubs collected in the field, as early as 
April 26 and until August 17, and the earliest and latest dates of pupa- 
tion observed were on the same dates. Flies from caged material issued 
from May 24 to September 4, the length of the puparium period ranging 
