316 Mr. A. E. Cameron on the 
appear that a lowering of the temperature effects a retarda- 
tion of development, the larval stage at higher temperatures 
(70°-78° F.) occupying but ten to fourteen days. Again, 
it seems rather anomalous that although the period of 
feeding is five to six times as long, the larvae never attain 
the same size, but always remain somewhat smaller, the 
pupae and imagines being correspondingly diminutive. 
Several other authors have experienced like results in the 
case of other Muscid larvae. Another factor associated 
with development is humidity. Variations in humidity 
have a similar effect to variations of temperature, a large 
amount of moisture acting as a check on development, just 
like a low temperature. Where there is little moisture 
development is hastened to a remarkable extent; but it 
must be also observed that a certain amount of moisture 
is always necessary to the larva for the proper assimilation 
of its food. 
Farsky observed that the larvae feeding on decaying 
beetroot in the open, required six to eight weeks for their 
development according to the weather conditions. 
The full-grown larva (figs. | and 2) measures 9 mm. in length, and 
is of the cylindrical form usual in Muscid larvae, gradually tapering 
postero-anteriorly, the posterior end rounded and rather obliquely 
truncate. The colour is dull white, the cuticle being perfectly 
smooth, devoid of hairs and exhibiting a faint iridescence in speci- 
mens preserved in alcohol. There are in all twelve very distinct 
segments, including the head or most anterior. The organs of 
locomotion consist of small ellipsoidal areas (figs. 1 and 2, kw.) 
interposed between each two segments, commencing between the 
third and fourth. These are beset with transverse rows of minute, 
closely-set spines, which give the larva a grip on any roughnesses 
of the surface over which it may chance to be travelling. They are 
the ‘‘ Kriechwiilste ’’ or ‘‘ Kriechschwielen”’ of German authors as 
opposed to the “‘ Zwischensegmente ”’ or tween-segments by which 
are meant small intercalary segments between any two true adjacent 
segments. At the posterior end (fig. 3) the larva of L. chorea is 
devoid of tubercles or protuberances of any kind and herein differs 
from the larvae of other members of the Sapromyzidae which possess 
a transverse row of four conical tubercles on the penultimate seg- 
ment, whilst many of the Lonchaeinae have small wart-like projec- 
tions on the last segment behind the stigmata. The two dark- 
brown, almost sessile posterior spiracles (figs. 3 and 4, p. sp.) are 
of the shape of equilateral triangles with the angles rounded off. 
