SEVENTEENTH ANNUAL REPORT. 



389 



Fig. 50.— Egg of 

 Boophilus annu- 

 latus of North 

 America. Great- 

 ly enlarged. 

 Original. 



stome) of the body (fig. 54) and scutum. Viewed from above, it usu- 

 ally presents a square to elongate surface, the posterolateral corners 

 (fig. 54 p. I.) of which are often sharply pointed and 

 spine-like. The outline varies in different species and 

 genera. In some cases it presents a sharp lateral pro- 

 jection. In the females two porose areas (areas porosae, 

 f()va3 poroses) are found on the upper surface (fig. 60). 

 These structures have different outlines in different 

 kinds of ticks, and are occasionally mistaken for eyes. 

 Anteriorly the base bears the mouth parts (fig. 54) or oral 

 appendages known as the hypostome, mandibles^ mandilm- 



lar sheaths^ 

 and paljpi. 

 The hypo- 



stome, mandibles, and 

 mandibular sheaths, are 

 together sometimes called 

 the A^ms'Z^^^ZZ'i^m (proboscis, 

 or, with some authors, the 

 rostrum). In some writ- 

 ings the terms proboscis 

 and rostrum also include 

 the palpi. 



(2) The litjpo stome 

 (tongue, labium, or rad- 

 ula) (fig. 54) lies ventrally 

 underneath the mandibles, and is best seen on ventral view. It is an 

 elongate dart or spatulate structure, which is composed of two lateral 

 symmetrical halves (figs. 53, 

 55). Its ventral surface is 

 armed with numerous minute 

 teeth, called denticles^ their 

 points being directed toward 

 the body. As a rule there are 

 numerous denticles at the tip, 

 which are not arranged in dis- 

 tinctly regular rows. A short 

 distance from the tip the den- 

 ticles become larger and are 

 arranged in quite regular lon- 

 gitudinal rows. In most spe- 

 cies these rows are so placed 

 that the corresponding denti- 

 cles of each row form a more or less regular transverse row. The 

 number of longitudinal rows varies in different species, and forms an 



Fig. 52. — Dorsal view of capitulum, or head, of male Boophilus 

 annulatus of North America. Greatly enlarged. Original. 



Fig. 53.— Ventral view of capitulum of male Boophilus 

 annulatus. Greatly enlarged. Original. 



