418 
Journal of Agricultural Research 
Vol. XXI, No. 6 
setae just above the lab rum. Mouthparts (Pi. 76, L) and mandibles 
(PI. 76, K) are the same general shape as in the first instar, though much 
larger and somewhat more heavily chitinized. The labrum is a small 
fleshy triangular piece. The labium and maxillae are fused and exist 
only as fleshy lobes bearing three pairs of minute setae and four pairs of 
very slight elevations or tubercles. 
The body bears 9 pairs of spiracles, a pair to each of the last 2 thoracic 
and first 7 abdominal segments; the setae are so small that it is almost 
impossible to locate them definitely, although there are apparently 4 
rows on the ventral surface of the 3 thoracic segments, 2 lateral rows, 
and 2 subdorsal rows extending the entire length of the body, 1 seta on 
each segment in each row, with the exception of the last abdominal 
segment which bears 2 pairs of subdorsal setae. As indicated previously, 
the 5 pairs of mandibles found in the cell slide where an individual of 
Fig. ii.— Homoporus chalcidiphagus: Lateral view of full-grown larva. X 24.7. 
this species had pupated indicate that there are four larval molts dur¬ 
ing the development of this species. 
The feeding habits of this larva are very much the same as those of 
Ditropinotus aureoviridis, though the larvae are very much more delicate 
and less active; consequently, they are more difficult to rear to full- 
grown larvae. Observations on 42 larvae of this species showed that 
they became full-grown in glass cells in from 5 to 25 days, depending 
upon weather conditions and the condition of the host. During the 
summer they developed very rapidly, while in the fall the period was 
greatly lengthened. The average period of development was about 11 
days. The average period of time between the full-grown larva and the 
prepupal stage for 40 individuals was 4X days. In a large number of 
cases the larvae became full-grown and remained quiescent for many 
months. Many then contracted slowly and died, while others completed 
their development to adults the following season. In one instance 2 larvae 
remained in the quiescent stage from August, 1917, until September, 
1918, when they finally died. At the present time, December, 1919, the 
writers have living larvae in the quiescent stage which became full-grown 
larvae as early as June, 1918. The winter is passed as full-grown larvae 
in the cells of the jointwomi. 
