The Ants of the Baltic Amber. 
57 
about as long as broad, moderately convex, with nearly straight, 
entire anterior border. Frontal area large and distinct, triangulär. 
Frontal carinae short, each continued back into the mesial border of 
one of the antennal scrobes. Antennae long and robust, 12-jointed, 
with a 3-jointed club; first funicular joint nearty as long as broad, 
joints 2 — 8 much broader than long, joints 9 and 10 a little broader 
than long, terminal joint large, glandiform, as long as the two 
preceding joints taken together. Thorax scarcely longer than the head 
and distinctly narrower, somewhat broader in front than behind, with 
rounded humeri and convex, rounded pro- and mesonotum and without 
traces of pro- and mesonotal and mesoepinotal sutures. Epinotum in 
profile with subequal base and declivity, the former slightly flattened, 
the latter concave, armed with a pair of short, erect teeth which are 
about as long as br :ad at their bases and further apart than long. 
Metastern al angles sharp and erect, forming a pair of teeth somewhat 
smaller than those of the epinotum. Petiole and postpetiole short, 
compact and convex above, the former about as broad as long, without 
a distinct peduncle but with a well-developed anteromedian ventral 
tooth, the latter nearly twice as broad as the petiole, fully twice as 
broad as long and but little narrower than the first gastric segment, 
which is very convex above, hemispherical, and with the terminal 
segments forming a pointed cone, which is directed forward and 
down ward. Legs robust; middle and hind tibise with well-developed, 
pectinated spurs. 
Female. Resembhng the worker but larger and with the typical 
structure of the female thorax, which is very short and compact, 
with well-developed, blunt teeth on the epinotum and compressed, 
pointed metasternal angles. The petiole, post-petiole and gaster resemble 
the corresponding parts of the worker. Wings with a discal and two 
cubital cells. Genotype: Myrmica duisburgi Mayr. 
Agrcecomyrmex duisburgi (Mayr). 
Myrmica dvisburgi Mayr, Beitr. Naturk. Preuss. I, 1868, p. 87; Taf. V, Figs. 87, 88, 
Dalla Torre, Catalog. Hymen. VII, 1893, p. 109; Handlirsch, Foss. 
Insekt. 1908, p. 874. 
Worker (Fig. 22a und b). Length between 4 and 5 mm. 
Mandibles and clypeus longitudinally, antennal scrobes trans- 
versely, and head, antennal scapes, thorax, petiole and postpetiole very 
coarsely and reticulately rugose. The spaces between the rugae are flat 
and apparently smooth. First gastric segment sharply longitudinally 
