1914] Kershaw—The Alimentary Canal of a Cercoyid 71 
but not invariably leaves its old froth and covers itself with fresh 
spittle on a new rootlet. 
The total length of an adult Tomaspis saccharina is 7—8 mm., 
or a full quarter-of-an-inch, from the head to the tips of the tegmina. 
In Cicada (a moderate-sized species common in Trinidad was 
examined) instead of the rectum descending from the posterior end 
of the diverticulum, it descends from the anterior. The malpighian 
tubes, also, descend from the anterior part of the diverticulum to 
the rectal valve without any return portion within the pouch, as 
there is in Cercopid; so that on the whole, perhaps, the alimentary 
system of Cercopid is slightly more complicated than that of 
Cicada. The malpighian tubes of Cicada fork very near their 
point of origin, as shown in fig. 5. 
In the Psyllid (Freysuila dugesti Aleman, also common in Trini- 
dad on the so-called Cedar) the arrangement of the alimentary 
canal is as simple as in Aleyrodes, but there are four malpighian 
tubes; these originate from the rectum at a great distance apart 
from one another.!. The two middle tubes were much shorter than 
the end ones in the specimens dissected. 
I send these notes to Psycue chiefly because the figures form a 
continuation of a former paper therein on the alimentary canal of 
various Homoptera, and owing to pressure of economic work on 
this Cercopid in Trinidad I shall probably be unable to add much 
to them. Unfortunately I have neither a copy of Licent’s paper 
nor of my own previous paper in Psycus, in which, however, Dr. 
Licent’s paper is referred to. In conclusion it must be added that 
I am greatly indebted to Prof. P. Carmody, Director of Agricul- 
ture, Trinidad, who very kindly had the foregoing analyses made 
in the Government Laboratory, and, moreover, gave valuable 
suggestions and assistance in the chemistry of this Cercopid. 
I have also to thank Mr. H. S. Shrewsbury, who made the analyses. 
EXPLANATION OF FIGURES. 
Tle d, diagrammatic transverse section of 
a, diagrammatic longitudinal section of pouch, much simplified. 
diverticulum or pouch. 2 
b, diagrammatic transverse section of  d, exterior view of alimentary canal of 
diverticulum or pouch. adult Tomaspis. 
c, external diagrammatic lateral view. — e, exterior view looking on anterior end. 
1“Text-book of Entomology,” Packard, 1903, p. 320. 
