34 



PART I. GENERAL ACCOUNT 



со e III 



Fig. 22. Transverse section through the postannular region of the metasoma of a female Sibo- 

 glinum caiilleryi. 



can - median coelomic canal ; eg - gland cells of the dorsal shield ; сое III- coelom of the metasoma ; 

 dgt - duct of pyriform gland ; gt - pyriform gland ; fm - muscle fibres of the ventral vessel ; ml - 

 layer of longitudinal muscle; my- muscle cell of the ventral vessel; nd- dorsal nerve strand; 

 pgt - pore of pyriform gland; vd - dorsal blood vessel; vv - ventral vessel. (After Ivanov, 1960a.) 



The cuticle and its derivatives 



The cuticle 

 The cuticle consists of a transparent colourless substance which often 

 stains differentially. It appears to be formed as a result of the secretory 

 activity of epidermal cells, in whose distal parts small granules and droplets 

 of secretion are often visible, staining in the same way as the cuticle and 

 merging into it (Fig. 37). Sometimes the cuticle consists of two layers — a 

 thinner stainable inner layer and an outer layer. The thickness of the cuticle 



