420 Mr. H. St. J, Donisthorpe on the Colonisation of 



hosts are ants of the genus Myrmica, which may be called 

 the beetle hosts. The beetles thus have to make a double 

 migration, one in the early part of the year from Myrmica 

 to Formica nests, and again in summer or autumn from 

 Formica to Myrmica. Consequently one would expect to 

 find Atcmeles at large more often than other regular guests, 

 and this is exactly what does happen. The pairing time 

 is about May, and takes place in Formica nests, it is the same 

 as that oi Lomcchusa. Father Wasmann has demonstrated 

 that the eggs of Atcmeles are laid on the eggs of the ants, 

 from which they are undistinguishable even with a lens. 

 The young larvse hatch very soon and devour the ants' 

 eggs. Another interesting point is that the beetles go 

 into quarantine before they enter the other hosts' nest, 

 after leaving the one. This is several days when leaving 

 Myrmica, as they remain hidden in and near the new Formica 

 nest ; Wasmann has often proved this in observation nests, 

 etc. When going from Formica to Myrmica the period is 

 much longer, as they are not found with the latter before 

 the end of August or the beginning of September, though 

 they have long before disappeared from the Formica nests. 

 Having been bred in the latter nests, the nest aura is no 

 doubt more pronounced in the beetles of the summer 

 migration. 



Atcmeles emarginatiis, Pk. 



Primary hosts. — Myrmica scabrinodis, Nyl., laevinodis 

 Nyl., ruginodis, Nyl., and stdcinodis, Nyl. 



Secondary host. — Formica fusca, L. 



F. Smith once recorded he took a specimen which ran 

 out of a nest of F. rufa. (Trans. Ent. Soc. Lond., 1842, 

 p. 151.) 



The record in Parfitt's "Col. Devon, 1867," p. 22, "in 

 nests of F. rufa, Plymouth, Reading," is no doubt incorrect, 

 as it is recorded in the " Ent. Annual" for 1858, p. 83, as 

 taken by Reading in nests oi Myrmica rubra near Plymouth. 



Penzance district in nests of F. rufa. ("Vic. Hist. 

 Cornwall," 1906, p. 190.) 



Here again I expect the ant was incorrectly recorded, 



Mayr once found a single specimen with F. rufa, and 

 Westhoff one with Tetraviorium cacspitum. 



I took a specimen by sweeping near a nest of Formica 

 Tvfa on May 15th, 1894, at Guestling. 



