576 Notes in 1887 upon lepidopterous larve, ce. 
fore, yields entirely to the influence of gravity, and 
bends sharply, forming a right angle with the rest of 
the body when the larva is in a horizontal position on 
the under side of a twig or leaf, less than a right angle 
when the larva is vertical. If, however, the larva be 
touched, the stimulus instantly causes muscular con- 
traction, and the normal Sphinx attitude is temporarily 
assumed. Perfectly healthy larve, in a vertical position, 
may sometimes also be seen to so far yield to the strain 
that avery extreme form of the attitude is produced, 
with less than a right angle between the anterior and 
posterior parts of the body, but I believe that the bend 
is never sharp except in diseased larve. Touching such 
healthy larve also causes them to take the more normal 
position for a time. It is curious that the term Sphinx, 
employed to describe this attitude, only really applies to 
the one position, which does not clearly exhibit its real 
meaning and significance. The muscular adjustments 
which are suited to counteract the strains chiefly felt in 
other positions are the cause of the attitude when the 
larva is in the true position of the Egyptian Sphinx, 
viz., extended horizontally along the upper side of a twig. 
But it will be observed that the attitude is never strongly 
marked under these circumstances. Thus in fig. 5 of the 
plate illustrating my paper on the ontogeny of Sphinx 
ligustri (Trans. Ent. Soc. Lond., 1885, Plate VII.), the 
larva is represented in an unnatural position, for I now 
see that a larva in which this attitude is so pronounced 
must have been seated on the wnder side of the twig, or 
more probably on a vertical twig, with the head upper- 
most. Plate XVII., fig. 5, of the present paper repre- 
sents the Sphinz-like attitude as it is commonly assumed 
on the upper side of a twig. Further support for these 
conclusions is found in the fact that the attitude does not 
appear to occur in the larve of Sphinx convolvuli, which 
feed on a creeping food-plant. 
5. THE GRAPHIC METHOD OF REPRESENTING THE GROWTH 
OF LEPIDOPTEROUS LARV&.—I was led to apply this 
method to larve in order to institute a comparison 
between the rates of growth in the two English species 
of Sphinx. The fact that S. convolvuli is so much 
smaller than S. ligustri at the beginning of the larval 
ontogeny, and so much larger at the end, seemed very 
