180 LIVERPOOL BIOLOGICAL SOCIETY. 
The salivary glands, at first simple pyriform sacs, be- 
come slightly branched, and their cavities become much 
narrowed. ‘The paired ducts run from the glands in the 
anterior part of the thorax to a point just behind the 
subcesophageal ganglia, and then unite to form the median 
duct (SJ). fig. 7) opening into the groove on the hypo- 
pharynx already described. 
The circulatory system consists of heart and aorta. The 
heart is a tube running above the alimentary canal from 
the anterior end of the eighth segment forwards to the 
anterior end of the abdomen where it ends suddenly, 
giving off the aorta from its ventral border, and this runs 
forwards to end in the cerebral ganglionic mass. The 
hinder end of the heart is open, but I have not been 
able to discover valves here: they are however not easy 
to see elsewhere and it is probable that they really exist 
though I have not seen them (or 7). At the anterior 
end, ¢.e., in segment I., a pair of apertures open into the 
heart and are guarded by valves directed backwards. 
Similar valves, but directed forwards, guard paired ostia 
in segments III. to VII. inclusive, but I have seen neither 
valves nor ostia in segment IT. 
The heart is held in position by numerous filaments 
attached to the dorsal body-wall, and by ale cordis. In 
what follows I am describing only what I have made out 
by the ordinary methods of dissection and section-cutting, 
and simple staining with picrocarmine, my object being to 
determine the anatomical rather than the histological 
characters of the pupa, and my views on histological points 
will therefore hardly have the same weight attached to 
them as those of the great investigator of Insect-hearts, 
Graber. Of the anatomical relations of the “ septum” of 
Graber, I have however no doubt, though they are 
entirely different from those described by Graber (7) in 
