416 
Journal of Agricultural Research 
Vol. XXI, No. 6 
this parasite in the vicinity of Charlottesville. Eupelmus allynii is un¬ 
doubtedly largely responsible for this condition of affairs, although D. 
aureoviridis very probably assists greatly in bringing about the condition 
which has been noted above. The larvae of H. chalcidiphagus are very 
smooth and inactive and apparently are as easy prey to other parasites 
as are the Harmolita larvae. Eupelmus allynii and D. aureoviridis , on the 
contrary, are very active and therefore can defend themselves to a large 
extent. This is particularly true of D. aureoviridis , which is very hairy 
and very active and usually can crush the egg of other parasites before 
hatching is possible. 
HOSTS 
Homoporus chalcidiphagus has been reared from field collections of the 
following species of Harmolita: tritici , vaginicola, secalis, horded Harris, 
elymicola , and atlantica. It is a primary parasite of the jointworm. 
During 1918 a number of experiments were conducted in order to learn 
whether it could be induced to breed as a secondary parasite. In most 
of these experiments it refused absolutely to oviposit upon any larvae 
except Harmolita, though in a few instances it oviposited upon Eurytoma 
sp. and in a single instance one larva developed upon a pupa of Ditro - 
pinotus aureoviridis . In some instances when the larva of Eurytoma 
sp. and the egg of H. chalcidiphagus were transferred to cell slides the 
egg was crushed by the activity of the larva. From this it would appear 
that when H. chalcidiphagus happens to oviposit in Harmolita cells 
containing larvae of Eurytoma sp. in the field, a large part of these never 
reach maturity. 
EGG 
The egg (fig. 9) is elongate, slender, kidney-shaped, slightly larger at 
the anterior end. It is circular in cross section and without pedicel or 
flagellum. It is white in color, and the surface is very smooth. The 
average length of 4 eggs was 0.4204 111m. and the 
greatest width 0.1347 mm. They are always found 
external to the host. Sometimes as many as 4 or 5 
were found in one cell of Harmolita, tritici , but never 
more than one larva completed its development when 
more than one egg was placed upon a single host. 
Fig. 9 — Homoporuschaiddi - Some of the eggs for some cause or other shriveled 
phagus . Eggs, x 47 5- U p and failed to hatch. This was not due to han¬ 
dling, since the eggs were found to be shriveled when the jointworm cells 
were opened. In hatching, the larva ruptures the large end of the egg and 
begins feeding before it completely emerges from the shell. The period 
of incubation in glass cells varied from i to 4X days, depending upon 
weather conditions, warm weather accelerating and cool weather 
retarding development. The average length of the egg stage of 71 eggs 
observed was about 2.5 days. 
