34 BULLETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 4, NOS. 1-2. 
These ants are very small and cannot be conveniently picked 
up by the forceps, but may be collected in almost any number by 
placing pieces of filter paper soaked in sugar solution near the 
nests. They collect on the paper to feed upon the sugar and may 
be easily shaken into a bottle. 
When distilled 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 potas- 
sium hydroxide solution it loses all odor, but on adding dilute 
sulphuric acid to excess an odor closely resembling that of fresh 
cocoanuts is developed. From this it is quite evident that the 
odorous principle is an ether of some sort. Attempts to identify 
the free acid were not successful; its odor is too pleasant to 
associate with any of the lower straight chain fatty acids, but may 
possibly be due to a forked chain one, or to a higher fatty acid. 
It does not seem likely that it is an aromatic acid. 
III. CAMPONOTUS MACULATUS, VAR SANSABEANUS. 
All the castes of this ant, and more especially the males, 
possess a strong, sweet pelargonic smell which very closely re- 
sembles a bouquet of valerianic and butyric ethers. The odor is 
at first concealed by the stronger smell of formic acid, but is very 
pronounced when an aqueous distillate from the ants has been 
neutralized with an alkali. This physiological peculiarity readily 
serves to separate it from Camponotus fumidus, an allied form 
which often greatly resembles it in the worker major caste, for 
the latter species is wholly devoid of the geranium-like odor.* 
IV. FORMICA FUSC A VAR. GNAVA. 
This ant, too, has its own distinctive odor, which can be readily 
recognized after the aqueous distillate has been neutralized with 
an alkali. The odor is exactly that of the mixture of sodium 
palmitate and oleate, which give to ordinary soap its odor. 
V. CREMASTOGASTER LINEOLATA, VAR. CLARA. 
The odor associated with this ant is one of the most unpleasant 
that we have encountered in the course of our work. At first the 
fresh ants have quite a strong odor strikingly similar to chlorine. 
* We are thus enabled to repeat on a small scale in the animal 
kingdom, the physiological sej^aration of species by olfactory means, 
a thing which has often been effected by botanists with plant species, 
more notably among the roses (cf. Kerner and Oliver, '95). 
