STINGS. 



I 740 ] 



STINGS. 



three pieces — a short, stout, cylindrico-coni- 

 cal outer piece or sheath (PI. 34. fig. 14 a), 

 cleft throughout its length on the under 

 surface and obtuse at the end, within which 

 are partly contained two long elbowed setse 

 or lancets (PL 34. fig. 15, one of them), 

 thickened and furnished with teeth directed 

 backwards near the end of one margin, the 

 other margin sharp and cutting. These setse 

 play within the sheath, being partially pro- 

 trusile and retractile, as is the sheath itself. 

 The poison-apparatus consists of two glan- 

 dular elongated sacs, either simple (PI. 34. 

 fig. 14 e,/), or branched as in the humble 

 bee, &c., and terminating by one (fig. 14f/) or 

 two ducts, in a muscular reservoir (fig. 14 c), 

 from which an excretory duct runs to the 

 base of the sheath of the sting. 



The irritation produced by the sting of one 

 of these insects needs no remark. It does not. 



Fig. 701. 



however, serve a merely defensive purpose, 

 but is used also to paralyze the prey, so that 

 it may be kept in store for future use. 



The sting represents a modified ovi- 

 positor. 



BiBL. Lacaze - Duthiers, 

 Aim. Sc. Nat. 3. xii. xiv. 

 &c. ; AVestwood, Intrud. ; Sie- 

 bold, Vergl. An. 



STINGS OF Plants. — 

 These are epidermal struc- 

 tures, consisting of large hairs, 

 with a bulbous base more or 

 less included in a cellular 

 coat,'and attenuated upwards. 

 In the sting of the nettle the 

 apex is expanded into a little 

 bulb, which is broken oft" when Kettlt 

 the sting is lightly touched ,j^ go diams. 

 (PI. 28. fig. 8). Young stings 



stinging hair of 



Pig. 702. 



Fig. 703. 



Fig. 704. 



Fig. 702. Gastric mueous gland with cylind^r-opitlK^liiim, from the pylorus of a dog. a, principal cavity; 

 6, tuBu)ar processes arising from it. Magnified <iO diameters. 



Fig. 703. Gastric peptic gland from the middle of the stomach, a, principal cavity; 6, primary, and c, terminal 

 branches arising from it. Magnified 60 diameters. 



Fig. 704. Portions of a terminal branch, the upper representing a longitudinal, the lower a transverse section, 

 a, basement membrane; b. large cella in close apposition with it; c, smaller epithelial cells surrounding the 

 cavity.^ Magnified 350 diameters. 



