The Ants of the Baltic Amber. 109 



Giesomyrmex hornesii Dalla Toere, Catalog. Hymen. VII, 1893, p. 176. 

 Gesomyrniex hornesi Ern. Andre, Bull. Soc. Zool. France, XX, 1895, p. 82; Haxd- 

 LiRSCH, Foss. Insekt. 1908 p. 859. 



Worker. Length 2,5 — 6 mm. 



Body slender. Head, excluding the mandibles, a little longer 

 than broad, as narrow behind as in front, with distinct but rounded 

 posterior corners and straight or feebly excised posterior border, very 

 short cheeks and convex vertex. The head is broadest through the 

 eyes, which are even larger, more convex and more reniform than 

 in G. annectens, being more than half as long as the head and more 

 approximated anteriorly. They project beyond the lateral borders of 

 the head when it is seen directly from below. Ocelli minute. Frontal 

 area and frontal groove obsolete. Clypeus fully as long as broad, 

 anteriorly projecting as a long, rather narrowly rounded lobe over 

 the bases of the mandibles. The surface of the clypeus is convex 

 posteriorly but its projecting border is flattened or slightly concave. 

 Mandibles very long, decussating when closed, with 9 long, acute 

 teeth, some of which are slightly shorter than others. The outer 

 borders of the blades are straight at the base, then feebly concave 

 just behind the convex tips which are bent downward. The basal 

 border is nearly as long as the apical, the mandible being broadest 

 where the two borders meet, although its breadth at this point is not 

 more than a fifth of 

 its total length. Palpi 

 and antennse more 

 slender than in G. 

 annectens, the scapes, 

 which are somewhat 

 incrassated at their 

 tips reaching a little 

 beyond the middle Fig. 53. Gesomyrmex hotmesi Mayr. Worker, B 18396. 

 of the eyes; all the 



funicular joints longer than broad. Thorax very similar to that of 

 G. annectens but more slender, the mesonotum longer and passing 

 into the metanotum somewhat less abruptly. Petiole as long as broad, 

 its node low, a little more than twice as broad as long, compressed 

 anteroposteriorly, rounded and blunt above, with convex anterior and 

 posterior surfaces. Gaster elongate elliptical with a circlet of coarse 

 anal cilia. Legs rather slender. 



Sculpture, pilosity and coloration as in G. annectens, the longitudinal 

 striation of the mandibles, cheeks, clypeus and front, however, more delicate. 



