86 M. O. Strobelt on the Anatomy and 



to recognize them as organs of the sense of touch, especially 

 as one of the nerves penetrating into the antennae can be dis- 

 tinctly traced to them. The name of " tactile papillse " or 

 " tactile bacilli" therefore appears to me to be very appropriate 

 for them. 



Organs of Digestion. 



The digestive apparatus (tractus intestinalis) comprises the 

 following organs : — the buccal organs, the oesophagus, the 

 stomach, the small intestine, the large intestine or colon, 

 and, further, the Malpighian vessels and the salivary glands. 



The buccal organs of Hcematopinus tenuirostris are placed 

 in the fore part of the head, not quite in the middle, but ap- 

 proximated to the ventral surface. The fore part of the head 

 has an indentation of the temporal margins before the apex 

 (fig. 8), then becomes a little enlarged, and is produced in 

 front into a fine tube, which shows a small emargination on 

 the ventral- side. Out of this tube or u sheath " (proboscis) 

 there can be protruded a sucking-rostrum, which attains half 

 the length of the head, and, according to Giebel (13, p. 43), 

 when protruded is moved briskly about like a tactile organ. 

 At its anterior end the sucking-rostrum bears a circlet of small 

 hooks (tig. 9, d) , which, when in a state of repose, are directed 

 backward and lie close to the rostrum. But when the rostrum 

 is pushed forth, the little hooks become erected so soon as the 

 circlet has issued from the sheath. The tube cannot then be 

 completely retracted again until the hooklets have again bent 

 backwards. How these hooklets are moved it was impos- 

 sible to ascertain, from the delicacy of the organ under consi- 

 deration and the difficulty of preparing it. Beyond the circlet 

 of hooks the extremity of the rostrum is arched into a hemi- 

 spherical form, and terminates at last in a fine point (fig. 9f). 

 The latter is at any rate the termination of the prickle observed 

 by Denny in Pediculus vestimenti (see Denny, 10, pi. xxvi. 

 fig. l,e-A). By means of this prickle the animal produces a 

 wound, and fixes its rostrum into this with the hooklets. 

 The rostrum consists of firm clear chitine. Posteriorly it is 

 connected with a " kind of internal chitinous skeleton M as 

 Landois (24, p. 36) very characteristically names it. Thus 

 on each side of the rostrum there is a dark-coloured chitinous 

 band (fig. 8 a and fig. 9 a). These chitinous bands, except 

 for a small indentation close behind the circlet of hooks, run 

 straight until, a little in front of the antennae, they turn right 

 and left at an angle of about 135°. Attached to these bands 

 at about their middle, and turned towards the rostrum, are a 

 second pair (figs. 8 and 9 &), which are at first closely ap- 







