1914} A Study of Dryophanta Erinacet. 1 
It was observed in all early stages that the excretion of the 
fluid was under the control of the larva, being poured forth 
freely when required. When a larva was found not feeding on 
plant tissue the body was dry. When a parasitic larva rested 
on the host both were bathed in a colorless fluid. If the larva 
of Dryophanta erinacei was placed on a glass slide or foreign 
substance, it immediately poured forth an abundance of fluid. 
It was evident that a reserve must be retained in the tubules. 
In a longitudinal section, (Fig. 45, Pl. VI.), it will be noticed 
that the small proximal cells (indicated by V.) on each side of 
the lumen are arranged so as to press closely against those 
opposite. This formation appears constant throughout the 
various stages, and we believe has a valvular function. 
A number of tubules were dissected out from larva of the 
earlier stages in normal salt-solution. This solution was 
allowed to evaporate, and the salt crystals formed used in 
grinding up the dried tubules. To the powdered mass a few 
drops of normal saline were added, and when all was dissolved, 
the fluid was filtered. The filtrate was treated with 85% 
alcohol, and the action brought down a heavy, white, floculent 
precipitate, which suggested that something of an enzymic 
nature might be present. This phase of the investigation was 
not pursued further at this time. 
Fresh material was again obtained, the Malpighian tubules 
dissected out as above, thoroughly dried, and ground with 
powdered carborundum, which reduced them to a finer powder 
than the salt-crystals. The powdered mass was dissolved in a 
few drops of normal salt-solution and filtered. The filtrate 
was injected with a hypodermic syringe into the midrib of the 
white oak leaves, one drop being used to each puncture. The 
operation was repeated three times on several leaves. Checks 
were made, normal saline being used in these. The solution 
containing the Malpighian tubule product penetrated from one- 
fourth to one-half an inch in the fibro-vascular bundles of the | 
midrib. The tissue was turned yellowish brown, and cracking 
appeared similar to that seen in many young leaves where the 
gall formation has just started, but owing to the death of the 
larva, has ceased. While these experiments did not produce a 
gall, they give suggestions as to the work performed by the 
secretion of the tubules. Nothing of the above described 
appearance was to be seen in the checks. E 
