TRAGARDH, ON DEVELOrMENT OF CLITOSTETHUS ARCUATUS. 5 



The maxillae (Fig. 14, Pl. I.) have either lobus externus 

 and lobus internus fused, or the former is completely reduced; 

 whichever is the case, we notice a thin-walled, reniform 

 plate, which joins the stipes with very narrow base: it has 

 4 — 5 stout and short spines near the median edge and two 

 long pointed hairs anteriorly. 



The maxillary palps (Fig. 14, Pl. I.) are three-jointed 

 and taper gradually towards the top; the terminal joint is 

 as long as the other two together, nearly cylindrical and 

 rounded at the top, where 5 — 6 small bliint spines and one 

 pointed hair are inserted. 



The labium is broad and projects on a level with the 

 anterior edge of the labrum, so that the labial palps, which 

 are single-jointed and placed near the median line, are plainly 

 visible on dorsal view. 



The body is almost cylindrical and tapers gradually from 

 the metathorax towards the posterior end; it consists of 3 

 distinct thoracic and 10 abdominal segments, the terminal 

 one of which is not however visible on dorsal view. 



The cuticle is minutely spinulated (Fig. 5, PL I), the 

 spinulse which are thickenings of the cuticle being narrow 

 and pointed; thej^ are longer on the legs than on the body. 



The pleurae of all segments except the terminal and 

 subterminal one project as horizontal conical processes; those 

 of the thorax are more rounded, whereas the other are tri- 

 angulär in outline. 



The prothorax is slightly narrower and shorter than the 

 meso- and metathorax, which are of equal size. 



Hairs. The dorsal side is provided with numerous, 

 regularly placed hairs which differ in size and number in the 

 different stages. The hairs are of two kind, viz. finely pointed, 

 setiform hairs and glandular hairs. The former are, as a rule, 

 to be found at the top of the lateral processes, the latter 

 occur on the dorsal side. 



In the first larval stage the thoracic segments have 

 one pair of slender lateral hairs each, which point nearly 

 straight outw^ards and slightly upwards and are inserted on a 

 higher level than those of the abdominal segments; around 

 the base of these hairs there are 3 — 4 small inconspicuous hairs. 



On the dorsal side, near the median line, they have one 

 pair of hairs each, and of these the meso- and metathoracic 



