286 
Acanthia lectularia 
supplied with bristles which here are simple, and arranged more or less 
in pairs as regards their position on the organ, and all pointing to the 
tip. Since it acts as a sheath, it is formed of fairly stout chitin, with 
the exception of the extreme tip, which is covered with sensory papillae 
and has on its surface a few very fine pointed bristles (Fig. 8). With 
this delicate tip the bug locates the spot where it is to feed, and a 
full-fed bug, when meeting a famished one, has been seen by the writer 
to protrude its proboscis horizontally towards its approaching relative, 
though why this was done remains a mystery. Famished bugs when 
imprisoned under a very shallow watch glass, tested the nature of the 
glass with the rostrum. The tip of the proboscis encircles the stylets, 
and, no matter how deeply they be inserted, it always surrounds them 
as in the case of the mosquito. 
When describing the rostrum, Landois says that its apex has 
“ slightly-outward-turned corners.” The writer believes this to be 
wrong, and refers to Fig. 8. 
To enable the lancets to penetrate deeply, since the proboscis sheath 
itself does not enter the wound, the latter bends towards the bug at 
the articulations, and especially at the articulation between the first 
and second joints (Figs. 6 and 7). Here the chitin is, so to speak, 
“ mitred ” away so as to allow of the great bending made necessary by 
very deep penetration (Fig. 9). 
Diagrammatically the relative positions of the rostrum and stylets, 
in relation to the head when sucking, is shown in Fig. 9. 
The protecting groove is open all its length, and only where it 
joins the head is it covered, and here the labrum or upper lip, which is 
a small triangular piece articulated to the anterior dorsal surface of 
the median prominence of the head, covers the groove (Fig. 3). 
When discussing the labium and labrum, Landois gives each an 
extra joint, and thus makes the former have four joints, and the latter 
two. Probably this had been due to an idiosyncrasy of his “ School ” 
of Zoology, as the joints can be seen very clearly. 
Inside the groove of the rostrum, as has already been said, are to 
be found the lancets (Fig. 11). These are composed of the mandibles and 
maxillae which have been transformed into long needle-shaped organs 
beautifully adapted for piercing, and united together to form a tube for 
the conveyance of the blood on which the bug is to feed (Fig. 10). 
Of the four component parts of this tube the maxillae are the most 
dehcate. They alone are serrated, and for only a short distance at 
their tips, the serrations being so placed that they act as barbs when 
