296 
Acanthia lectularia 
having arisen before there was fluid to imbibe. It would also appear 
that the suction is spasmodic, as the air can be seen collecting as separate 
bubbles. 
Landois states that the maxillae are unequal in length. The writer 
finds that they are equal, and suggests that the error may have been 
due to the relative positions of the maxillae, after the alternate move¬ 
ment, on withdrawal. 
In describing the method of inserting the stylet tube Landois says : 
“ Die Bewegung des Stechrohres ist zunachst eine mittelbare, indem 
bei Hebung und Senkung der Unterhppe, in deren Einne es belegen ist 
eine gleiche Bewegung der ersteren erfolgt ” (Part 1, page 209, lines 
4, 3, 2 from foot). On the next page, however, he says : 
“ Wahrend des Stechens bleibt die Unterlippe unbeweglich liegen ” 
(Part 1, page 210, lines 22-23). 
The writer is at a loss to say what Landois really meant. 
Even under ideal conditions for feeding, the bug does not always 
settle down at once to enjoy its meal. On one particular occasion 
observed by the writer, the lancets were inserted nine times in different 
places before the insect was satisfied with the spot. When finally 
suited and at work, the feeding process took about eight minutes, the 
glistening bands beginning to appear at the end of four. The first 
sign of satiety is a curious jerking of the antennae, then, the sucking 
tube being smartly withdrawn, the bug makes off with considerable 
speed, the rate being much the same whether full or famished. 
Measurements taken before and after feeding, show that the greatest 
increase iti bulk is in the dorsal to ventral direction. 
Before 
After 
6 mm. 
3 mm. 
2 mm. 
Length 5 mm. 
Breadth 3 mm. 
Thickness 0-5 mm. 
In the process of feeding there is no external sign of pumping, the 
head chitin being so thick that it conceals all movement, although the 
striated pump muscles are very strong and in bulk fill up the major 
part of the head. As previously mentioned, they are fastened to the 
bristle-free area of the upper surface of the head (Fig. 3). Their ventral 
ends are fastened to the dorsal surface of the “ pump,” i.e. crop (Figs. 
14 and 15). This organ is a pear-shaped chitinous swelling of the 
pharynx, which at the anterior end communicates directly with the tube 
formed by the lancets, while posteriorly it leads into the oesophagus. 
