TRÄGÅRDH, ON DEVELOPMENT OF CLITOSTETHUS ARCUATUS. / 



than in tlie subsequent ones,, is placed on low conical tubercles 

 close to the median line and points obliquely backwards and 

 upwards; two pairs are placed dorsolaterally, close togetber; 

 of these the median pair is very small and points obliquely 

 forwards and upwards, whereas the lateral pair, which is more 

 than twice as long as the median one, but not half Bo large 

 as the dorsal hairs, points nearly straight outwards or shghtly 

 backw^ards. 



The glandular hairs (Fig. 8, a, b and c, Pl. I) resemble 

 very much the glandular hairs described from several cater- 

 pillars. They are hollow tubes, slightly wider at the base 

 and at the top, where they widen to a cup, the edge of which 

 is divided into 4 — 5 minute teeth. 



Textfig. 3. Textfig. 4. 



Textfig. 3. Projection of 9^'^ abdominal segment, with locomotorial bristles. 



dorsal view. 

 Textfig. 4. Top of abdomen, side view. X 150. 



The 9^^ segment has no glandular hairs, but is, at the 

 posterior angles which are slightly projecting, prov id ed with 

 two pairs of stout and very sharply pointed bristles (Textfig. 

 3) the use of which has been related above. When the 

 top of the abdomen is examined on lateral view we notice a 

 short conical processe at the top of which the anal aperture 

 is situated; this is probably the 10^^ + 11^^ segment (Textfig. 4). 



When the larva has attained the length of 1,2 g mm. it 

 becomes motionless, remains so during twenty-four houres, 

 whereon it leaves the old skin which splits dorsally along the 

 middle of the thoracic segments. 



