1907.] Wheeler, The Polymorphism of Ants. 29 



intermediates, which I have called pseudogynes, gradually bring about a 

 degeneration of the parasitized colonies. 



"Within the Lomechusa group an important ethological difference 

 obtains between Lomechusa and Aiemeles, inasmuch as the former is 

 homoecious, i. e., the species of this genus have each but a single host (a 

 species of Formica), in whose company they complete their whole life-cycle; 

 Avhereas the Aiemeles are heteroecious, since as adult beetles they live with 

 Myrmica rubra and a species of Formica, but have their larvae reared only 

 by the latter. The fact that Lomechusa has only a single host explains the 

 more highly developed 'passive stage of its symphily. This is evident from 

 the one fact among others that the beetle is more affectionately treated by its 

 normal hosts and is fed, not like an ant, but more like an ant-larva. The 

 heteroecious character of the Aiemeles, which are compelled twice during 

 their life time to change their normal hosts, once in the spring when they 

 migrate for reproductive purposes from Myrmica to Formica, to have 

 their larva reared by the latter, and once in the summer or autumn, when 

 they migrate from Formica to Myrmica for the purpose of hibernating, 

 enables us to explain the greater active perfection of their symphily, their 

 greater initiative towards the ants, and the closer imitation of their behavior. 

 The last peculiarity is especially apparent in that they do not, like Lome- 

 chusa, Claviger, and Amphofis, beg the ants for food merely by stroking 

 them with their antennae, but also raise their fore-feet after the manner of 

 ants, and stroke the cheeks of the regurgitating hosts. On this account 

 "they are treated by their normal hosts like ants and not like ant-larvae." 



Five species of Lomechusa and a greater number of species and varieties 

 of Aiemeles have been described. Of these L. strumosa is the best known. 

 It is exceedingly rare in England/ but appears to be more abundant in cer- 

 tain parts of the continent, especially in Holland and Luxemburg, where 

 Wasmann has been carrying on his investigations. Its normal host is the 

 blood-red slave-maker (Formica sanguinea), though very rarely it may be 

 found in the nests of F. rufa and p-atejisis. 



In the present article we are mainly concerned with the pseudogynes 

 mentioned in the above quotation. Wasmann has subjected these indi- 

 viduals, which were well known to ForeP and Adlerz,^ to a searching exami- 

 nation, and describes them as follows:^ 



* According to Donisthorpe (Record of Capture of Lomechusa at Woking with Formica 

 sanguinea. Entomologist, XXXIX, July, 1906, p. 163), only three specimens have been recorded 

 from England. Hesides the one referred to in his article, one was "taken by Sir Hans Sloane 

 on Hampstead Heath in 1710, the other found by Dr. Leach in the mail-coach between Gloucester 

 and Clidteiihiim." 



2 Lcs Fouiniis de la Sui.sse. Zurich, 1874, p. 138. 



3 Myrmecologiska Studier. II Svenska Myror ocli deras Lefnadsforhallanden, Bihang. 

 Svenska Vet. Akad. Handl., XI, No. 18, 1886, p. 76. 



* Die ergatogynen Formen bei den Ameisen, I. c, p. 612. 



