NO. 10 



MORPHOLOGY OF GNATHOTRICHUS — SCIIEDL 



43 



widest at the base, decreasing in width towards the apex. The first 

 visible sternite is the longest and is separated from the second by a 

 suture which is only visible under high magnification. It is very 

 likely that the first visible sternite contains elements of more than 

 one abdominal segment but they are not indicated by sutures or lines. 

 Medially the first sternite is produced into a long process called the 

 intercoxal process, which extends far between the metacoxae. From 



Fig. 22.—GnathotricJuts retusus Lee. : Seventh tergite of female. 

 A. dorsal aspect; B, ventral aspect; Sp-, seventh spiracle. 



the base of this process a ridge arises which extends laterally, sepa- 

 rating the part of the sternite covered by the metacoxae from the 

 remainder. At the antero-lateral corners this ridge is developed into 

 a clavicula. In this clavicula (b) articulates the ventral part of the 

 postepimeral hook. The surface of the uncovered part of the first 

 sternite bears numerous hairs which are arranged in concentric rows 

 encircling the metacoxae. Punctures are sparse. All the other ster- 

 nites are separated from each other by deep septae and they have the 

 shape of short rectangular plates of nearly equal length. They are 

 all heavily chitinized and armed with long hairs arranged in a trans- 



