THE L\'TERXAL STRUCTURE OF ANTS. 



45 



become fatal to the ants. This is easily demonstrated when Campo- 

 notinx are confined in a vial and irritated till they discharge their 

 secretions. But as there seems to be little or no acid in the poison of 

 any .--pecies except those belonging to this subfamily, Janet's con- 

 jecture, at least so far as the accessory gland is concerned, is far 

 from being applicable to all ants. 



The repugnatorial, or anal glands (Figs. 22 and 23), were dis- 

 covered by Forel. They are present only in the female and worker 

 Dolichoderinse and coexist with well-developed poison glands of the 

 bourreleted type. They consist of grape-like clusters of large, spher- 

 ical gland-cells, the fine intracytoplasmic ducts of which unite to form 

 a pair of much larger ducts that open into the posterior portions of 

 two large, thin-walled sacs, dorsal to the poison gland and closely 

 applied to each other in the medium sagittal plane of the ant's body. 

 These sacs have muscular walls and serve as reservoirs for the gland- 

 ular secretion. They have a common opening just dorsal to the anus. 

 Their secretion is quite unlike that of 

 the poison glands described above, being 

 more sticky and having in nearly all 

 Dolichoderin?e a very characteristic 

 odor, which Forel calls the " Tapinoma 

 odor " because it is very noticeable in 

 the common species of this genus in 

 -Europe and North America ( T. errati- 

 citin and sessile). Others aptly describe 

 the odor as that of " rotten cocoanuts.'' 

 Melander and Brues have studied the 

 secretion in Iridoiiiynne.v analis (Fore- 

 lins fa-tidus) and find that "when dis- 

 tilled with steam the odor passes over 

 and remains dissolved in the aqueous 

 distillate. Thus freed it retains the very 

 evident odor of rancid cocoanuts. By 

 saponification with potassium hydroxide solution it loses all odor, 

 but on adding dilute sulphuric acid to excess an odor closely re- 

 sembling that of fresh cocoanuts is developed. From this it is quite 

 evident that the odorous principle is an ether of some sort." During 

 conflicts with other ants the Dolichoderinae smear the secretion of their 

 repugnatorial glands on the bodies of their enemies, and from the 

 behavior of the latter it is evident that the liquid is fatal, or, at any 

 rate, very irritating, and that it constitutes a most efficient protection 



FIG. 23. Sagittal section 

 through tip of gaster of 

 worker Bothriomyrnie.r mcri- 

 dionalis. (Forel.) a, Orifice 

 of repugnatorial vesicles ; b, 

 anus ; c, orifice of poison 

 vesicle ; d, orifice of acces- 

 sory gland ; e. vaginal orifice ; 

 /, terminal ganglion of ven- 

 tral cord : g. repugnatorial 

 gland of right side. 



