A STUDY OF COMPSILURA CONCINNATA. 7 
area where the gypsy moth is not found, though colonization has 
been made there. It is true that it will perpetuate itself without the 
eypsy moth, but not in such large numbers, as collections made from 
these outlying towns have shown. 
During the years 1912 to 1916 the entomological branch of the 
Dominion of Canada collected in New England and shipped for 
colonization to New Brunswick and Nova Scotia 32,824 Compsilura 
to combat the brown-tail moth. In 1914 and 1915 assistants of the 
branch of Cereal and Forage Insect Investigations of the United States 
Bureau of Entomology collected and sent Compsilura to Arizona 
and New Mexico to be used in the fight against the range caterpillar 
ITemileuca oliviae Ckll., a total of about 4,000 of these parasites 
eing divided between the two States. During the years 1915 and 
1916 about 3,000 Compsilura were sent to Florida to be used against 
the fall army worm (Laphygma frugiperda 8. & A.). Compsilura 
has not proved as successful in the West and South as it has in New 
England up to the present time. In Arizona and New Mexico the 
conditions are so radically different from those in New England 
that even though the parasite becomes established it will take some 
time for it to became climatically adjusted. It has been too recently 
colonized in the South to justify predictions as to the results that 
will be accomplished. In Canada it more nearly approaches its 
standing, as an effective parasite, in the outskirts of the brown-tail 
moth infestation in New England and in time should prove a valu- 
able aid in the control of this pest. 
SPREAD. 
The rate of spread of Compsilura has been determined in two 
ways: (1) By scouting, which consists of carefully examining gipsy 
moth and brown-tail moth infestations in localities just outside the 
area previously recorded as covered by Compsilura, and (2) by 
collections of various lepidopterous larve from towns beyond the 
known spread of the parasite. This rate of spread has been found 
to be approximately 25 miles per year, and this is taken into con- 
sideration in colonizing the parasites, the colonies having been put 
out in most cases about 25 miles apart in all directions. This proves 
that the insect is a strong flier, for there are no artificial means 
worth considering that will assist in its dispersion. 
RECOVERY. 
The first recovery of Compsilura was made in New England in 
1907, a single specimen reared from a field collection of gipsy-moth 
larve. Attempts to recover this parasite failed in 1908, but in 
1909, soon after colonization, several puparia were reared from col- 
lections of both brown-tail moth and gipsy-moth larve, which 
