STEUOTUEE AXD BIOLOGY OF SCHIZOXEURA LAXIGERA. 665 
(1745), was of the opinion that they excreted a sweet fluid 
and were concerned with the respiratory and excretory system, 
this view being adopted by Kyber (1815), Morren (1836) and 
Kaltenbach (1843). Linne (1758) expressed the opinion that 
a honey substance was secreted from the cornicles, and this 
view was fairly generally adopted. Of more I'ecent authors, 
Witlaczil (1882) considered that sugary substances were 
excreted from the cornicles. Biisgen (1891), refei*ring to 
analyses made by Knorr on the secretion produced from the 
cornicles, showed that it must be regarded as a waxy 
substance. Mordwilko (1995, p. 363) has demonstrated the 
waxy nature of the substance underlying the cornicles in 
Lachnus viminalis. Horvath (1904), in his paper, “ Sui- 
tes cornicles ou nectaires des Aphidiens,” concludes, as the 
results of observations made, that the cornicles are secretory 
canals from wax-producing glands, specially differentiated, 
the product of which is a waxy fluid, which affords a means 
of protection against the predaceous larvae of Cocciuellidee 
and Chrysopidte. According to this author the honey 
substance which attracts ants is produced in clear droplets 
from the anus. Some American authors (Gillette, 1908), 
have confirmed Horvath’s observations. The author has 
frequently observed in S. lanigera large clear and trans- 
parent drops emerging from the anus, which were quite 
colourless. Buckton (1875, p. 47), has described similar drops 
in the case of Schizoneura ulmi. (See also Mordwilko, 
‘ Biol. Centrlb.,’ xxvii, 1907, pp. 212 et. seq.) 
The Head and its Appendages (figs. 1, 3, 22-24, 35). — 
The head is borne at the anterior end of the body, and 
bears the oral appendages which surround the mouth. At 
its proximal end it broadens out to become continuous with 
the prothorax. Towards its distal end it becomes narrower, 
and is strongly deflexed. It is divided by a pseudo-articula- 
tion of membranous chitin (a. /.) into a broad, proximal 
])ortion, the epicranium, which bears the small eyes and the 
antenuEe; and an anterior tapering portion (/V.), which 
includes the clypeus and labrum. This anterior portion is 
