406 
Indiana University Studies 
TYPES. — 1 female and 1 male in the Museum of Comparative Zool- 
ogy. From Ravinia, Illinois; May 1, 1916; Q. alba; L. H. Weld collector. 
While bicolens is unknown except from Triggerson’s and 
Wieman’s studies, Weld’s material, and my southern Indiana 
and Kentucky series, the insect is of course to be expected 
wherever the galls of the agamic generation occur in abun- 
dance. The galls of bicolens are not usually visible until after 
the buds have opened and, as Weld (1926), suggests, “The 
easiest way to rear the flies is to locate a tree in the fall well 
infested with the hedge hog gall and from this tree gather 
twigs in the spring just before the buds start, putting them in 
a bottle of water and setting the whole in a battery jar with a 
cloth over the top.” 
This bisexual insect is very close to gemmula , the bisexual 
form of prinoides; and the bisexual forms to be discovered for 
for the other eastern species and varieties of Acraspis will 
probably need careful comparisons in making determinations. 
Altho the agamic females have oviposited late in the fall or 
early winter, it is not until nearly six months later, after the 
middle of April, that the eggs hatch. Adults were mature and 
emerging from my southern Indiana material on April 22 and 
May 1, 8, and 9 (1927). Wieman (1915) secured adults at 
Cincinnati over a period of two weeks beginning April 23, 
1914. Weld (1926) reports pupae near Chicago on April 28 
(1913), and adults on May 1-20 (in 1913), on May 6 (1924 at 
Washington) , and May 17 (1909 near Chicago) . Triggerson, 
who first recognized on the basis of both laboratory and field 
observations, that this represents the bisexual generation of 
erinacei , did not find the eggs hatching to produce these bi- 
sexual insects at Ithaca, New York, until after May 8. Quot- 
ing from Triggerson : 
“On the twelfth of May a slight swelling, at the apex of 
which an empty egg shell was visible, appeared on the lower 
green portion of the scale . . . This proved to be a freshly 
formed gall, containing a young larva of Dryophanta erinacei. 
The gall at this stage was thin-walled, with a pebbled surface, 
greenish in color, and contained a watery fluid. The egg-shell 
remains attached to the apex of the gall until the latter has 
reached considerable size, when it dries up and disappears. 
These hypertrophies develop rapidly, as many as three ap- 
pearing on one scale. The wall of the gall has by this time 
