Parasitism of brown-tail moth in America. 
151 
shape) was held in position by a tack which passed through it into 
the wooden strip. The end of this cone, passing through the bottom 
of the cage, permitted a third glass tube (/) similar to the two above 
mentioned, to be held in position. Xo further support to this tube 
was Deeded than that afforded by the cone itself. 
In using this cage a mass of cocoons of the brown-tail moth was 
placed in the tray, and the cover was put on with the several tubes 
in position. Tachinid maggots issuing from the prepupal caterpillars, 
08- pupflB contained in the cocoon mass, in attempting to seek the 
earth would pass through the bottom of tin 4 tray and be conducted by 
the still" paper funnel into the lower tube, where they were quickly 
noticed and easily re- 
moved. All other 
parasites, as well as 
the brown-tail moths 
themselves, when they 
emerged, were at- 
tracted by the light 
into the two upper 
tubes, and could be 
similarly removed 
with little difficulty. 
(See PI. Y. fig. I.) 
By the aid of this 
contrivance we were 
enabled to secure a 
quantity of the larvae 
of the unknown tach- 
inid. already men- 
tioned, within a few 
minutes after they 
had issued from the Fio. 10.-^-Baaring eage for tachinid parasites of the brown-tail moth* 
i i i ,i m i I a. Paper funnel; b, cleats holding paper funnel in position; r, tray: 
IlOSl, ana ineiel>\ ae- nooden strip un outside of cage; e, paper cone connecting paper 
temuned that the fail- funnel a and glass tube /; /(, //. paper funnels supporting glass 
ureof this species to tob *''* <)riKinal 
pupate was in no way due to the unnatural surroundings. Some- 
times the tubes were partly filled with damp earth, in order that 
these larva 4 might immediately come in contact with it, and at other 
times the larvae were removed as soon as they dropped and placed 
upon earth similar to that which they would naturally have encoun- 
tered had they issued from cocoons in the field under wholly natural 
conditions. 
The use of these cages also saved a large amount of exceedingly 
painful work which would otherwise have been necessary in determin- 
ing whether or not Parexorista chelonidb was present in any of the 
field collections. 
