90 
William Morton Wheeler. 
7650/364, 7699/413, and 979/583 and, in the same Collection, two 
specimens (7517/231 and 9649/558), which he doubtfully referred to 
this species. 
lridomyrmex goepperti Mayr. 
Hypoclinea göpperti Mayr, Beitr. Naturk. Preuss. I, 1868, p. 56, Taf. I, Figs. 3 — 7, 
' Taf. III, Figs. 42-46, $ 9 cf. 
Bothriomyrmex göppertii Dalla Torre, Catalog. Hymen. VII, 1893, p. 170; Ern. 
Andre, Bull. Soc. Zool. France, XX, 1895, p. 82; Handlirsch, Foss. 
Insekt. 1908, p. 871. 
I was at first inclined to adopt the view of Dalla Torre and 
subsequent writers that this ant is a true Bothriomyrmex, bnt a closer 
study convinces me that it is more probably an lridomyrmex. The 
thorax of the worker, to be sure, is much like that of Bothriomyrmex 
in having a rather feeble constriction in the mesoepinotal region, but 
this is also the case in certain species of lridomyrmex, notably in the 
North American I. analis Ern. Andre. The head of the amber species 
is certainly not like that of any existing species of Bothriomyrmex 
known to me, but narrowed anteriorly, with slightly concave cheeks 
and its posterior portion is broad and subcordate as in most species 
of lridomyrmex. Moreover, the maxillary palpi are 6-jointed, the labial 
palpi 4-jointed, and there is considerable Variation in stature just as 
there is in some recent species of lridomyrmex. This latter character 
and also certain peculiarities of the head, especially of the clypeus, 
with its straight anterior border and the inflated, slightly projecting 
sides, especially in large specimens, together with the obsolescence of 
the sutures between the clypeus and head and the absence of a distinct 
frontal area and frontal groove, recall the conditions in the genus 
Liometopum. Mayr gives the length of the worker as 3,4 — 6 mm. 
I regard the later measurement as excessive and as probably referring 
to other species of lridomyrmex, probably I. samlandicus, which may 
have been confounded with the species under discussion. It is not 
improbable, however, that I. goepperti represents an ancestral and 
generalized form from which both Bothriomyrmex and Liometopum have 
been derived, the former by a reduction of the number of palpal 
joints, the latter by an increase in the stature variability of the 
worker and of the pilosity and pubescence of the body. 
As Mayr has adequately figured and described all three phases 
of I. goepperti I will here omit a detailed description. It is far and 
away the most abundant and dominant ant in the amber fauna. 
Mayr examined 580 specimens, Ern. Andre 309. I have seen 4539 
specimens which are distributed as follows: 3686 workers and 2 fe- 
