1907.] Wheeler, The Polymorphism of Ants. 15' 



ever, there were several of these annectant forms. As this could hardly be 

 a mere coincidence, we must assume that there is some connection between, 

 the existence of intermediates and the presence of the parasites. 



D. Other Chalcidid Ant-Parasites. 



From the observations recorded in the above paragraphs we may safely 

 conclude that the remaining Orasema species, of which quite a number have 

 been described by Cameron, Howard, and Ashmead, are parasitic on ants 

 and have life-cycles analogous to that of 0. viridis. Still other genera, 

 however, of the enormous family Chalcididse, contain ant-parasites and 

 these, though very imperfectly known, may be passed in review before I 

 proceed with an account of a very different type of parasitism. For the 

 sake of convenience we may distinguish three groups of cases, first the ant- 

 parasites of the sub-family Eucharinae exclusive of Orasema, second those 

 belonging to other subfamilies, and third, the cases too imperfectly known 

 to be referred to any particular genera. 



Among students of the Chalcididee the opinion seems to have been gaining 

 ground that the Eucharinse, which according to Ashmead's recent synopsis 

 (1. c. pp. 266-270) comprise some 25 genera, are largely, if not exclusively 

 ant-parasites. Ashmead says that in this group "are found some of the 

 most singular looking and wonderfully shaped Chalcids known, the struc- 

 ture of the thorax, and particularly of the scutellum, being most wonderfully 

 and curiously modified and developed; and this development, in connec- 

 tion with the brilliant metallic green and blue colors of its members, makes 

 the group the most striking and attractive of any in the subfamily. Some 

 of the species are now known to be parasitic upon ants and probably the 

 whole group attacks these insects. In temperate regions the family is poorly 

 represented, but in tropical countries, where ants most abound and flourish 

 in enormous colonies, these insects are not rare and seem to have reached a 

 very highly specialized development." This extraordinary specialization, 

 which at once reminds us of that obtaining in other highly myrmecophilous 

 and termitophilous groups, like the Paussidae among beetles and the Termi- 

 toxeniidfe among Diptera, etc., is clearly shown in the figures of some of the 

 more striking Eucharine genera reproduced in this article (PI. IV, Figs. 56- 

 62). 



The first to describe a Eucharine parasite on ants was Forel.^ On 

 opening the huge cocoons of one of the Australian bull-dog ants {Myrmccia 

 forficata) he found several metallic green and coppery pupjie about a cm. 

 long, which a year later were described and figured by Cameron^ as those 



' Un parasite de la Mvrmecia forficata Fabr. Extr. C. R. Soc. Ent. Belg., I Fev. 1890, 3 pp. 

 2 Hymenopterologicai Notes. Mem. Lit. Phil. Soc. Manchester (4), IV, 1891, pp. 182-194, 

 1 pi. 



