The Ants of the Baltic Amber. 91 



males in the Geolog. Inst. Koenigsberg Coll. (XXB 626, XXB 52, 

 XXB 112, XXB 117, B 18750, XXB 1118, B 18645, XXB 7118, 

 XKB 137, B 18934, B 18812, B 27286, B 19441, XXB 1110, XXB 

 1114, B 19744, XXB 761, XXB 1531, B 18367, B 1845 etc), 650 

 workers, 2 males and 2 females in the Ki.ebs Coll. (K 1749, K 4244, 

 K4287, K2631, K 1757, K 859, K 1734, K 5784, K 941, K 3699. 

 K 1441, K 3545, K 1745, K 2624, K 2660, K 4492, K 1027, K 4058, 

 K 4468 etc.), 4 workers in the Brussels Museum, 46 workers and one 

 male in the Berlin Museum (240, 243, 247, 251, 257, 258, 294, 308, 

 314 etc.) and 73 workers and one male in the Haren Coll. (67, 104, 

 134, 291, 337, 859, 488, 980, 983, 1841 etc.). In addition to these 

 4539 specimens I have examined 174 of the 268 specimens recorded 

 by Mayr as belonging to the Physical Economic Society Collection (to 

 day the Geolog. Inst. Koenigsberg Coll.), including the types of the 

 worker and female. The male type, which I have not seen, was in 

 the Menge Coll. 



The occurrence of 2 — 4 specimens of I. goepperti in single pieces 

 of amber is not uncommon, and occasionally the number of indivi- 

 duals thus enclosed is much greater. Thus in the Klebs Coll. there 

 are the following inclusions: K 108 with 9 workers, K 4168 with 12, 

 K 886 with 15, K 828 with 15 and K 839 with 20 workers. And in 

 the Geolog. Inst. Koenigsberg Coll. three blocks without numbers 

 contain 27, 28 and 50 workers respectively. The great abundance of this 

 ant is also attested by the fact that it often occurs in the same block 

 with other species, especially with Lasius schiefferdeckeri and 1. geinitzi. 



In the Geolog. Inst. Koenigsberg Coll. there is one block of 

 amber (without a number) containing a worker /. goepperti with its 

 larvae and another block in the same collection (also without a number) 

 encloses 13 workers mingled with a number of Aphids! 



These various specimens seem to me to show conclusively that 

 I. goepperti was everywhere abundant in the amber forests, that it 

 formed populous colonies, whose workers foraged in files and attended 

 plant-lice on the oak and Pinites trees, much as the species of Lio- 

 metopum of the present day forage on the conifers and oaks in the 

 western United States, and on the oaks in Austria, Italy and the 

 Balkan Peninsula. 



Iridomyrmejc sa'inlandicus, sp. no v. 



Worker. (Figs. 43 u. 44.) Length 5,5—6 mm. 

 Head, excluding the mandibles, about as long as broad, convex 

 above, broadest in the middle, narrower in front than behind, with 



