200 [Auo. 



if the rooms be ceiled, otherwise they will drop from above, bringing along with 

 them their noxious prey m the act of contending for victory. 



For food thoy prefer fresh animal, or insectal matter. The larvae of other 

 insects, and the youns^ of all animals arc obnoxious to them, hence all heaps of 

 rubbish, and hiding places of such prey, when occurring in their route, are care- 

 fully explored. Hence, too, the Drivers, when returning from their predatory 

 excursions, atford some of the rarest and finest of the smaller specimens of Ento- 

 mology. 



Newly expressed oils are also favorite articles of food, especially the vegetable, 

 that obtained from the fruit of the Elais guiniensis — the Palm oil of commerce. 



The Drivers, thougli often a great annoyance, are not without their uses in the 

 economy of nature, They tend to keep down the rapid increase of noxious in- 

 sects and smaller reptiles. They consume much dead animal and vegetable 

 matter, which, constantly occurring in tropical climates, vitiates the atmosphere ; 

 and, which is not the least important, they compel the inhabitants to observe 

 habits of comparative cleanliness in their dwellings and on their premises, as a 

 filthy town or house is the sure object of frequent visits. 



The natives of Africa dread their approach, lor being almost naked, wearing a 

 narrow piece of cotton around their loins only, they are the more exposed to their 

 bites ; but more especially, say they, " because they deprive us of two things we 

 love most, jioullry and sleep. 



On the identiUj of Anomma with Dory I us, suggested hy sjiecimeiis whidb Dr. 

 Savage found together, avd transmitted to illustrate his paper on the Driver 

 Ants. By the Committee to which it was referred. 



In the letter transmitting his paper on the Driver ants to the Academy, Dr. 

 Savage says, "In the small vial you will find specimens of niMla,\\'kh three 

 very large individuals, which I consider the perfect insect. Now here is pre- 

 sented an interesting point of investigation, viz., the true relation of these larger 

 individuals to the Driver ants." These specimens afford a solution to a problem 

 which has engaged the attention of entomologists ; namely, the relation of the 

 Dorylides to the Formicidae, since the large ones alluded to belong to the genus 

 Dorylus. They are 13 lines long, and seem to be referrable to D. nigricans, and 

 they had cast their wings.. There is little to indicate an identity of species 

 between them and ruhella, as these want the holosericeous surfaces. The color 

 and texture of the head and mandibles agree, however, and the medial and poste- 

 rior coxne present a narrow excavation superiorly (for the reception of the femora 

 when elevated,) in place of the conspicuous cup-shaped one in the corresponding 

 limbs of the male. The mandibles in this sex are slender and have the apex in- 

 curved, but not falcate, and they are without teeth. The femora are extremely 

 compressed, and the abdominal peduncle is about as wide as the succeeding seg- 

 ment. 



There are two forms, both of arcr.ns and ruhella, one of which includes the 

 largest individuals, the mandibles of which are armed with one abrupt, erect, 

 medial tooth ; the other and more abundant form is variable in size, and the man- 

 dibles have two slender teeth directed forwards. The labial organs and maxilla? 

 are alike in both forms of both species. These organs cannot be compared in 

 ' Dorylus,' because, with the mouth, they are entirely wanting; the margins of 

 the labium and labrum bi/ing solidly united. 



