Dec, igoS.j WHEELER : STUDIES ON MYRMECOPHILES. 211 



It is probable that the primary, or regular hosts of these two Cremas- 

 toc/ii/i a.re to be found among the many species of Formica which abound 

 within the geographical range of P. occidentalis, and that this latter 

 ant is merely a secondary, or accidental host. This is indicated by 

 the fact that I have recently received from Mr. W. Knaus a specimen 

 of C. knochi taken at Stockton, Utah, by T. Spalding in a colony of 

 a very pale form of Formica sanguined subintegra Emery with F. sub- 

 polita slaves. 



In the same paper Wickham mentions the occurrence of Hetcerius 

 brunneipennis in the nests of Formica fusca var. subsericea, in company 

 with Ptomphagus parasita. 



Wasmann (The Guests of Ants and Termites, Entom. Record, XII, 

 1900, pp. 204, 205) publishes the following note on the common 

 European species : " Just one word about Hetcerius ferrugineus and its 

 allies. What seems easier at first sight than that a small Histerid, 

 which already possesses in its oval shape a kind of protection, should 

 force the ants to receive it as a lodger, and which would be tolerated 

 because of its being unattackable, and that finally the ants, taking 

 pleasure in licking it, would elevate it to the rank of a true guest. 

 But it is not as simple as it appears. In my observation-nests I 

 have had a number of Hetozrius for more than five years, and I have 

 come to the conclusion that it would be better for this species to be 

 merely tolerated. It is in truth licked by the ants, but this is not to 

 its advantage, as the ants do not feed it. It is often in great danger. 

 Formica sanguinea and pratensis play with it for a quarter of an hour 

 at a time, like a cat plays with a mouse, trying to get hold of its jaws, 

 so it is often hurt. Once a Hetcerius was so badly used by a Formica 

 sanguinea that it was half killed and nearly devoured. Whilst licking 

 the wounded beetle the ant's greed had been awakened." 



In a later paper (Zur niiheren Kenntnis des echten Gastverhaltnisses 

 (Symphilie) bei den Ameisen- und Termitengasten, Biol. Centralbl., 

 XXIII, 1903, p. 207) Wasmann makes a few remarks on the adipose 

 tissue and notices the large size of the ovarian eggs of H. ferrugineus. 

 He kept a pair of these beetles for more than three years in an arti- 

 ficial nest, but they never oviposited and he saw neither larvae nor 



pupae. 



Literature. 



1905. Aldrich, J. M. A Catalogue of North American Diptera. Smiths. Miscell. 



Coll.. XLVI, No. 1444, 1905, pp. 344-346. 

 1889. Bertkau, Philip. Ueber die Larven von Microdon. Sitz. Ber. Niederhein. 



Gesel. Nat. u. Heilk., 1S89, pp. 58-60. 



