16 XLIX. K. Šulc: 



thorax and mesothorax form a whole, but tlie metathorax and the 

 first four abdominal segments are each distinctly developed. 



On thehead few hairs only: 3—5 greater and 5 — 8 small above, 

 3 — 6 greater on the peripliery. The short, unjomted, antennae are 

 acuminated, rounded, truncate or excavated on the apex, with a 

 stout, long hair on the base. Mentum monomerous, short conical. 



There are following forms of ducts of ceriferous glands to be 

 discerned : 



I**- cylmdrical ducts (their openings: filiěres isolées,') crescent 

 shaped pores, autorům) (Tab. 2. íig. 2., segm 4"' ; Tab. 2. fig. 3. 

 b-d) which form short chitinous tubes with crescentshaped, elliptical 

 to circular, gaping openings at the distant end ; they are growing 

 broad and stronger proximally, showing in the optical section in their 

 middle a crownlike formation (kr) viz : a chitinous disc, closing up the 

 duet and bearing in its excavated centrum a thin tube inflated at 

 the end. 



It appears to be an arrangement for the adherence of the ce- 

 riferous gland. 



Cylindrical ducts are most narrow on the prothorax (Tab. 2. 

 fig. 2., I.) the farther behind they stay, the more they are growing 

 stronger ; they occupie the outer fourth of each segment, and form in 

 this way a „peripheric zone". Their distribution is not constant in dif- 

 ferent specimens, nor symmetrical on the samé individuum, 



2'"^ Serrated plates ^) ^) are also ceriferous ducts and therefore 

 I will call them serrated ducts. There open into them small tubes 

 (Tab. 2. fig. 4 d — e, tr; fig. 2, 3) and the „scale" itself is but a re- 

 servoir for the wax matter, which is flowing out of single fringes 

 (fig. 4 f, vn). I háve made this observation on a living insect; the 

 „scale" was almost cylindrical, half transparent with lighter and 

 darker places, so that it looked like a chessboard (Fig. 4 f.); the 

 fringes were fingershaped and from their ends were arising thin 

 threads. After having been treated with KOH the scale was getting 

 flat, transparent and the fringes acuminated. Serrated (fringed) ducts 

 are mightiest on the telson, they become smaller towards the head 

 and on the 2""^ abdominal segment they change into scales (resp. ducts) 

 simply rounded or angulated on the end, sometimes with a protru- 

 sion, probably the opening of the duet itself. 



They will be called transitory ducts (Tab. 2. fig. 4 c). 



3"^ Beginning from the 1'' abdominal segment the transitory and 

 fringed ducts disappear and are substituted by short conical ducts in 



