sid 
ba 3 
1914] Kershaw—The Alimentary Canal of a Cercopid 69 
The froth or spittle of the nymph appears to be a mucin or 
mucinoid, since it reacts to the usual tests for mucin; it granulates 
with sub-acetate of lead and stains deeply with methylene blue in 
glycerine and alcohol; the material taken from the malpighian 
tubes before it is poured into the gut also gives the xanthoproteic 
reaction. This mucinous substance is produced by the anterior or 
smooth portion of the malpighian tubes, which in the nymph is of 
larger diameter than the lobed part through being swollen with the 
secretion, whilst in the adult the reverse is usually the case. The 
nuclei of the smooth part of the tube take Delafields haematoxylin 
heavily; those of the lobed part mostly stain but faintly. If the 
smooth part of a nymphal tube is placed in alcohol, the contained 
mucinoid shrinks and coagulates and can be dissected out as a very 
pale yellowish, stringy substance. If this coagulated material is 
then placed in water, it quickly swells and becomes viscid, pale 
bluish-translucent and just like the untreated material fresh from 
the tubes. The alcohol and water treatment several times in suc- 
cession leaves the material practically unaltered after again placing 
itin water. The secreted froth is a very stubborn material, though 
it consists merely of air-bubbles coated with an exceedingly thin 
film of the mucinoid; in this, however, are numbers of crystals; 
those of calcium oxalate are numerous; uric acid, leucine pellets 
and urates are also present; also sodium and potassium chlorides. 
In fact every substance excreted from the anus of the nymph is 
found in the froth, but it is the mucinoid substance which accounts 
for the froth retaining its form more or less for three or four days 
after the nymph has abandoned it. Fragments of shed epithelium 
from the gut occur in the excrement of both nymph and adult. 
I could find but few crystals in the lobed portion of the malpigh- 
ian tubes; those of uric acid are large and there are numerous urate 
granules. But some of the cenocytes contain uric acid and calcium 
oxalate crystals and urates. These cells are exceedingly large, 
situated in a cluster on either side of the abdomen, and their outer 
membrane granulated with a claret-red color. They are, as usual, 
connected intimately to the trachee near the spiracles and also 
to the fat-body, which also contains urates, etc., in some of the 
cells. 
The blood of the nymph differs conspicuously from that of the 
adult; in the former it is nearly colorless, in the ee of a bright 
and clear oil-yellow. 
