The Ants of the Baltic Amber. 
21 
myrmex constrictus (7595/309 [Fig. 42J). Mayr, who discovered this 
singulär specimen, regarded it as a gynandromorph, but I believe 
that it is an ergatomorphic male of the extreme type, such as is found 
in a few recent ants, notably in males of Formicoxenus nitidulus and 
Ponera punctatissima, which have the head much more like that of 
the worker than in many ergatomorphic males of the genera Cardio- 
condyla, Symmyrmica and Technomyrmex. 
The larval and pupal stages of the Baltic ants were also in all 
respects as highly specialized and of the same structure as those of 
recent species. I have seen larvse and pupse of Iridomyrmex geinitzi , 
I. goepperti and Lasius schiefferdeckeri. The Lasius pupse are enclosed 
in cocoons, while those of I. geinitzi are naked, showing that the 
cocoon-spinning habit of the larvse had been lost in the Dolichoderince 
as far back as the early Tertiary. This is of considerabie interest, 
because it has been inferred from the occasional occurrence of both 
naked and enclosed pupse in the same colony of certain species of 
Formica (F. fusca, etc.,) that the loss of the cocoon is a mutation, or 
saltatory Variation of recent origin. This may, of course, be true in 
Formica and some other Camponotine genera, but it is quite as pro- 
bable, in view of the extraordinary persistence of small characters 
displayed in the preceding paragraphs, that the pupse of F. flori may 
have shown the same presence or absence of the cocoon in the same 
colony as is shown by the modern F. fusca. 
There are also unmistakable indications that the habits and in- 
stincts of the amber ants were nearly if not quite as advanced as those 
of existing forms. The method of their preservation and the close 
affinities of most of the species with modern arboreal forms have 
already been considered. That many of them had learned to attend 
plant-lice and had therefore become ,,trophobiotic u is shown by a block 
of amber in the Königsberg Coli, containing a number of workers of 
Iridomyrmex goepperti together with a lot of their Aphid wards. That 
the amber ants kept myrmecophiles in their nests can scarcely be 
doubted, for at least three genera of Paussidee ( Cerapterus , Pleuropterus 
and an undescribed genus) are cited by Klebs in his list of amber 
Coleoptera 1 ). That these ants also had Acarine parasites is shown by 
two workers of Lasius schiefferdeckeri in the Königsberg Coli., each 
bearing a mite attached to the base of one of the hind tibise (Fig. 58). 
9 Ueber Bernsteineinschlüsse im allgemeinen und die Coleopteren meiner Bern- 
steinsammlung. Schrift. Physik.-ökonom. Gesellsch. Königsberg LI, 1910, 2, pp. 217 
bis 242. 
