PERSECUTED AXD TOLERATED GUESTS. 



most of them are opaque or shining black, with coarsely punctate or 

 pitted surfaces. Their movements are very slow and awkward. The 

 larvae live in the debris of the nests, like the larvae of Cctonia, and 

 pupate in fragile earthen cocoons (Wheeler, 1908^). I have taken one 

 of the smaller red species (C. spinifcr) in a nest of Pheidole desertorum 

 in western Texas. C. canaliculatus, castanccc and harrisi are not un- 

 common in the nests of various species of Formica (schaufussi, c.vsect- 

 oides, subscricea, etc.) in the Eastern States. More rarely these same 

 species occur in nests of Componotus and Aphcenogaster. Schwarz 

 records C. knochi from the nests of F. subccnesccns in Colorado, and 

 in the same state I have taken many specimens of C. ivheeleri from 

 the nests of various forms of F. rufa. C. crinitus occurs in the nests 

 of F. c/nara in Texas, C. me.vicanus in the nests of the same ant in 

 Arizona. There is little doubt that the 

 true hosts of Cremastocheilus are species 

 of Formica and that the occurrence of 

 these beetles with other ants is either 

 secondary or accidental. In my artificial 

 nests the beetles were almost continua-lly 



j 



being dragged about by their legs, but 

 were neither fed nor licked by the ants. 

 These insects, however, persistently gnawed 

 at the anterior and posterior thoracic angles 

 of the beetles as if much attracted by the 

 trichomes (Fig. 231). I am inclined, 

 therefore, to regard the Cremastocheili 

 as degenerate symphiles. which are now 

 able to live as indifferently tolerated or 

 even as persecuted synoeketes, because their 

 hard armor shields them perfectly from 

 the mandibles of the ants. Even the mouth parts and antennae are 

 protected by the peculiar mentum, and the legs are so tough that 

 they cannot be disarticulated by the ants. I was quite unable to ascer- 

 tain the nature of the food of these beetles, some of which lived several 

 weeks in my nests without eating. According to Brauns (Wasmann, 

 19000 ) the Cetoniine beetles of the genera Plagiocheilus and Myrmeco- 

 cheilus, which are allied to Cremastocheilus, live in the nests of Plagio- 

 Icpis in South Africa. 



(c) Myrmecocleptics. Janet (1896?;) gave the name of myrmeco- 

 clepty to the peculiar behavior of the Lepismid Atelura [Lepismina] 

 fonnicaria, which is common in the nests of various European ants. 

 This insect is decidedly of the loricate type, with broad thorax, rapidly 



FIG. 231. Formica in- 

 tegra worker gnawing at the 

 hind thoracic angle of Cre- 

 mastocheilus castanea-. (Orig- 

 inal.) 



