June, ’24] 
MOSHER AND HOLBROOK: INFLATING DEVICE 
409 
method the larvae were usually much distended and had a very un¬ 
natural appearance. 
The amount of inflating work has increased greatly since the work 
was started in the spring of 1911 and the devices described here have 
been worked out by those having the work to do. Mr. C. B. Russell, 
who worked for several years in this Bureau, perfected a device by 
means of which compressed air can be utilized, the flow being regulated 
by needle valves. The tubes with the points and clips were in use on 
other inflating devices. The glass tube back of the clips so that a tip 
can be slipped off and another placed on after a specimen has been put in 
place, was designed by Mr. Holbrook. 
A great demand for inflated larvae of the gipsy moth and brown-tail 
moth was the cause of this apparatus being assembled at the Gipsy 
Moth Laboratory, Melrose Highlands, Mass. This has eliminated 
some of the tedious operations experienced by those engaged at this 
task and made the results more satisfactory. 
In the process of inflating, the two most necessary elements for good 
work and speed are a steady supply of air pressure and a sufficient ad¬ 
justable amount of heat to meet requirements. 
The apparatus and accessories being used at the Gipsy Moth Labora¬ 
tory are neither complicated nor difficult to assemble. The outfit con¬ 
sists of two units, namely, the oven and an air pressure tank. 
The oven is of ordinary galvanized iron 9" long, 7" deep and Wyi" 
high. Six inches from the bottom a horizontal metal partition divides 
this space into two chambers, an upper and lower. /The backs of both 
chambers are closed, the lower with metal and the upper with glass to 
admit light. The fronts remain open thus permitting the operator to 
inspect the gas burner in the lower and attend to the specimens in the 
upper chamber. Attached to the bottom of the front of the upper 
chamber are 2 pairs of metal clips that are used for holding the subjects 
over the heat. These clips are made of a ^"springy metal Zyi" tall 
and are spaced 3yi" between pairs. 
The air pressure reservoir is a Galvanized Expansion Tank ordinarily 
used in buildings heated by a hot water system. The pressure is forced 
into the tank with a bicycle pump through a valve stem placed in a 
yi" opening near the base. 
The tank was provided with a number of openings, some not being 
needed for our purpose. These extra holes were sealed with plugs such 
as are commonly used on steam boilers. 
