G-. S. Graham-Smith 
353 
the head is bent downwards bringing its posterior surface into view. The legs 
are then moved rapidly upwards and downwards causing the head to jerk 
from side to side. So rapid are the movements that the head appears to be 
rotating (PI. XVIII, fig. 20). 
The proboscis is cleaned with the anterior pair of legs, and the movements 
may be rapid or very slow. Both legs are used simultaneously, and the 
pulvilli, applied on each side of the extended proboscis, are passed along it 
from its proximal to its distal extremity. During this procedure the fly sits 
erect (PI. XVIII, fig. 14). 
The males of S. carnaria were chosen as subjects for these observations, 
because they are large, not readily disturbed, are somewhat sluggish in their 
motions, and have very large pulvilli, which are easily observed. Similar 
procedures for cleaning themselves are adopted by most of the commoner 
species of flies, and also by the hymenoptera parasitic on them. 
During the seasons of 1916 and 1917 the habits of the two closely allied 
species, C. erytlirocephala and C. vomitoria, were carefully noted. C. erylhro- 
cephala was caught in traps almost daily, but C. vomitoria only occurred 
commonly in the traps on fine days with little wind. C. vomitoria and H. 
dentipes seem to dislike great heat and are seldom found on windy days, 
especially if very hot. On the other hand Lucilia and 0. leucostoma are seldom 
caught in traps on sunless days, but are very common and active on hot, 
sunny days. 
It was noticed in both years that newly emerged flies are greatly attracted 
to excrement, and that in the early part of the season decomposing animal 
matter attracts few flies, presumably because the majority are not ready to 
oviposit. 
In October 1917 some much decomposed animal remains containing many 
small larvae were buried to a depth of 18 inches. This material was exhumed 
on February 13, 1918, when the larvae were found to be alive and nearly 
full fed. 
It may be of interest to record the fact that when digging in the face of 
a sand pit on April 20, 1917, two male Onesia cognata were found at a depth 
of 18 inches from the surface, and some inches from the face of the pit. A 
distance of 9 feet separated the two flies, which were very sluggish, but soon 
became active on exposure to the sun. 
EMPUSA DISEASE. 
The writer has shown previously (1916, p. 507) that records relating to 
the infection of flies, other than house-flies, with empusa are rare. He de¬ 
scribed the infection in four specimens of II. dentipes, two of F. canicular is 
and in C. erytlirocephala. 
In the year 1916 very careful observations were made and 34 specimens of 
H. dentipes infected with the disease were found outside between July 5 and 
September 11. In that year it was first seen in M. domestica on September 27. 
