216 PROCEEDINGS OF THE ACADEMY OF [Feb., 



more in search of food before returning to the nest and reveaUng its 

 hidden entrance, a tiny hole like a pin-prick in the soil or bark. 



None of the species are known to attend aphides, and the nests very 

 rarely or never contain guests or synoeketes of any description. The 

 Leptothorax themselves, however, sometimes live as guests in the 

 nests of larger ants. Thus L. Emersoni is always found as a guest in 

 the nests of Myrmica brevinodis, and L. acervorum of Europe and its 

 American variety convivialis also exhibit a decided tendency toward 

 xenobiosis. The typical L. curvispinosus appears to act as the slave 

 of Tomognathus americanus, an extremely rare ant, which is probably 

 similar in habits to its European congener, T. suhhwis. JMost of the 

 species of Leptothorax are very timid, and many of them readily 

 "feign death" when roughly handled. Nevertheless they are often 

 extremely hostile and vindictive toward other ants, especially toward 

 ants of their own species from strange nests. 



For our first insight into the habits of Leptothorax we are indebted 

 to Forel, who recorded his observations in the charming Fourrnis de la 

 Suisse (pp. 339-341). The more important of these observations are 

 given in the following translation : 



''April 17, 1868, I found in the bark of a pine-tree a very small 

 colony of L. tuber o-affiiiis, consisting of a fertile female, about a dozen 

 workers and some eggs. I lost four of the workers during the capture 

 and broke two of the legs of the female. I subsequent!}' placed this 

 little family in a pasteboard box with a glass cover. It prospered; 

 the female got on well with her four remaining legs ; some of the eggs 

 hatched and the larvae were fed. The workers would eat nothing but 

 the honey which I gave them; they were very timid and settled down 

 with the female in the box. They gave little heed to the female, which 

 lived almost like them. I have noticed that it is only the workers of 

 the genera Plagiolepis and Lasius and of certain species of Formica that 

 assiduously court their fertile females. Leptothorax goes to the opposite 

 extreme: the females live almost like the workers, being merely some- 

 what less inclined to work. Huber was wrong, therefore, in general- 

 izing the role of the fertile females of Losiiis, etc. By MsiV 24 the 

 female of my captive formicary had again laid some eggs, and the 

 larvse had grown very large. The workers ate larvne of Lasius that 

 were given to them. June 4 one of the larvse became a worker pupa, 

 but there remained only two large larv?e and the eggs. June 10 there 

 were two pupoe and eight or nine small larvse had hatched from the 

 eggs. Of the latter two were yellow and retained this color, the others 

 were whitish. By June 13 thev had srown. I then 2;ave mv L. 



