232 Proceedings of the Royal Physical Society. 
The Abdomen. 
The first five abdominal segments are similar and show prescutal, 
scutellar and hypo-pleural folds. 
The epi-pleural folds when the larva is viewed laterally are hidden by the 
hypo-plewral folds. The sixth, seventh and eighth segments have no prescutal 
folds. The ninth has no hypo-pleural fold, and the tenth segment consists 
of three lobes round the anus. 
Spiracles—tThe first eight abdominal segments each bear a pair of 
spiracles. The pair on the eighth segment are four times as large as 
the others, a peculiarity which, according to Perris, serves to distinguish 
the larve of Zyctus from all others. 
CLASSIFICATION OF THE LARVA. 
The larvee under consideration may be classified as follows :— 
A.—Feet five-jointed. Head more or less round, not deeply sunk in the 
thorax. Antenne showing only two joints. Pro-thoracic spiracles slightly 
larger than the others. Scutellar fold of pro-thorax not markedly broad. 
Spinules on the back and sometimes on the sides of the various segments. 
1. The meso-thorax has a prescutal fold. 
(a) Spinules on the prescutal folds of the meta-thorax and first 
8 abdominal segments. No spinules on the 9th abdominal 
segment . : : ; A. domesticum. 
(6) No spinules on the prescutal fold of the meta-thorax, but on 
all the prescutal folds of the first 8 abdominal segments, 
and on the sides of the 9th segment near the anus. Head 
markedly hairy. Spinules small : A, paniceun. 
(c) Spinules on the prescutal folds of the meta-thorax and first 
8 abdominal segments, on the scutellar folds of the 8th and 
on the sides and below the 9th. Spinules large E. mollis. 
(2d) Spinules on the prescutal folds of the meta-thorax and of 
the first 6 abdominal segments, and on the sides of 
the 9th . ; : : ake X, tesselatum. 
2, The meso-thorax has no prescutal fold. Spinules small. 
(a) Spinules on the prescutal folds of the meta-thorax and of the 
first 8 abdominal segments, on the scutellar folds of the meso- 
thorax and of abdominal segments 2, 3 and 4, and on the 
hypo-pleural folds of abdominal segments 2 to 8, and on the 
sides and below the 9th . : Ptilinus pectinicornis, 
