THE AMAZONS. 475 



bre-riccps very closely, judging from Forel's description (18990) and 

 a couple of type specimens which he has generously given me. The 

 Mexican form differs only in having very few or no hairs on the dorsal 

 surface of the body, and is hardly more than a variety of brci'iccps. 

 Its slaves are unknown but are in all probability some form of fusca. 

 I take from my note books the following observations on our other 

 amazons : 



( a ) Polyen/us brcviccps. This subspecies, which I shall call the 

 occidental amazon, is not uncommon in several localities in the moun- 

 tains of Colorado and New Mexico at altitudes between 2,000 and 2,500 

 m. I have also seen a few specimens that were taken at much lower 

 elevations in Illinois and Kansas. Of all our subspecies brcviccps 

 resembles the European type most closely. Its color, pilosity and 

 sculpture are practically the same, it forms rather large formicaries 

 and its slaves are much like those of rufescens. These comprise F. 



and ncoclncrca, ants so similar in size and color 



that they would be regarded as identical by any one but a myrmecolo- 

 gist. F. neocinerea occurs only in rich meadows, the two others on 

 dryer ground. The ratio of slaves to brci'iccps workers is the same as 

 that of fusca to rufescens in Switzerland. During the summer of 1903 

 and 1906 I witnessed several forays of breviccps in Cheyenne Canyon 

 near Colorado Springs and in Florissant Canyon, west of Pikes Peak. 

 One of the most typical of these forays was seen in the former locality. 

 An unusually large colony, containing fully 1,000 breviceps workers, 

 was found nesting under some large stones near the top of the steep 

 bank of Cheyenne Creek. The formicary extended out under the 

 stones and must have covered an area of fully 2.5 sq. m. Under the 

 edge of one of the stones was the single entrance, about 2 cm. in diame- 

 ter. July 20 at i P. M., after seeing a few breviceps and their slaves 

 (subsericca) loitering about the entrance, I stationed myself at the nest 

 in the hope of witnessing a foray. After waiting nearly an hour (at 

 1.55 P. M. ) I saw the beautiful red ants boil up, so to speak, in the 

 opening. In a few moments they came rushing out in great numbers 

 and kept running about just outside the entrance till 2.15, when they 

 started in a compact army up the embankment and obliquely in a south- 

 westerly direction. Soon, however, they returned to the nest as if 

 changing their minds and again started out due south and straight up 

 the bank. The procession formed with great alacrity and then pushed 

 ahead at the rate of one m. in forty seconds, over smooth ground, but 

 requiring about one minute to make the same distance over the dead 

 oak leaves. There was no leader, the army being headed by a few 

 workers which were continually being passed by workers overtaking 



