150 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
As may be noted by reference to the table, the imported parasites 
are beginning to become sufficiently abundant so that parasitism by 
them will compare favorably with that by American species, but are 
not as yet so abundant as to exceed the American species in relative 
effectiveness. The table as presented does not indicate at all accu- 
rately the actual status of the several species of parasites mentioned, 
on account of the difference in the condition of the material at the 
time of collection. 
Compsilura, for example, is much more apt to leave the cater- 
pillars before they spin for pupation, and the same is true of Meteorus. 
Monodontomerus, Pimpla, Theronia, etc., never attack caterpillars 
before spinning, and Monodontomerus and Theronia frequently 
reserve attack until some little time after the host has pupated. As 
it stands, parasitism by Monodontomerus is about equal to that of 
Theronia and in excess of that by Pimpla or Anomalon. Parasitism 
by Compsilura is distinctly more effective than that by all of the 
other native tachinid parasites of the caterpillars. Meteorus is much 
more common than indicated in the limited territory over which it is 
now known to exist, and the specimens reared represented the second 
generation of adults to develop upon the brown-tail moth in 1910. 
Apanteles lactevcolor Vier. is not represented in these collections, 
since it does not attack caterpillars so large as those involved. 
In carrying on this work several styles of rearing cages were used, 
of which one was devised for the special purpose of securing the 
tachinid parasites with the minimum of exposure to the effects of 
the irritating hairs of the brown-tail caterpillar. This worked very 
satisfactorily, and since it may possibly be found of service in con- 
ducting similar work elsewhere, the following description is presented: 
The basis of this cage (see fig. 10) consisted of a box of stiff paste- 
board 8 inehes square and 12 inches high. About 4 inches from the 
top a stiff paper funnel (a) was fitted and held in position by the 
cleats (6), which, in turn, were fastened to the sides of the box by 
broadheaded upholsterer’s tacks driven in from the outside. These 
cleats served to support the tray (c), which just fitted into the cage. 
The bottom of this tray was covered, in some instances with coarse 
mosquito netting, and in others with a wire screen of j-inch mesh. 
Two holes in the side of the tray corresponded with two 1-inch holes 
in the side of the box, and these in turn with similar holes in a wooden 
strip (d), which was fastened on the outside. When the tray was in 
position, paper cones (h) and large glass tubes (g) were inserted in 
these holes. 
The stiff paper funnel (a) had its apex inserted into another hole 
bored diagonally in a similar wooden strip which was fitted in the 
bottom of the cage. Inside of this hole a stiff paper cone (formed 
like h by rolling up a section of a strip of paper cut to a circular 
— ae 
