Vol. XXVII. 

 1910 



1 Lea, TJie Guests of Ants, Bees, and Tennites. 51 



the dehris thrown out by the ants ; they usually remain quite 

 motionless for some time, but then start up as if in a violent hurry, 

 and try to escape. 



Sticks on the ground will often be found on being split up to 

 be swarming with ants, and amongst these will often be found 

 other insects. The galleries of white ants are seldom productive 

 of insects, but nevertheless some species are to be found there 

 that are seldom or never obtained elsewhere. 



On thundery days, just before rain, nests seem to be more pro- 

 ductive than at other times, and singularly enough midsummer 

 seems to be the least productive period of the year, spring 

 being, perhaps, the best. 



Several singular facts are very conspicuous in a large collection 

 of ants'-nest beetles: — i. The large percentage of species (in 

 comparison with the total number of beetles) that are entirely 

 without eyes, or with extremely small ones. 2. The numbers of 

 species that have less than eleven joints (the usual number) to 

 their antennae. 3. Species having extremely small or hidden 

 palpi. 4. Species with receptacles for the legs and antennae. 



A large proportion of the beetles found with ants belong to the 

 family Pselaphidce, there being more of these than of all others 

 combined. They are all small and more or less reddish, and 

 move about amongst the ants in a most friendly manner. Any 

 collector who pays much attention to ants' nests, must come 

 across them, as they occur in the nests of most species of ants, 

 and, although never in large numbers, the nests of some species 

 are seldom without them. The genera most commonly found 

 are Articerus (remarkable for each antenna being apparently 

 composed of one joint, although there are really two, and for its 

 apparent absence of palpi), Euplectops (with strongly sculptured 

 prothorax), I'mesijohorus and Ctenisophiis (with very curious 

 palpi), Eupines (with prothorax highly polished, and without a 

 sub-basal impression, such as almost all other genera have), and 

 Pselaphus (with palpi often almost or quite as long as the 

 antennae). Other genera are found, but less commonly : 

 Somatipion (with apical joint of antennae curiously large and 

 round), Tyromorphus (with large palpi), Batrisodes and Batraxys 

 (with immarginate abdomen), and Clavigeropsis (like Articerus, 

 but antennae with more joints). In other parts of the world the 

 blind genera, Adranes and Claviger are known, but all our 

 species have eyes, although sometimes very small ones. 



Most of the Pselaphidce of ants' nests feed on mites, with which 

 the nests are often abundantly supplied. But some of the 

 Clavigerides have the mouth parts atrophied, and the fanciful 

 supposition has even been published that they are used for 

 scenting the nests. 



The ScydmcenidcB are very similar in appearance to the Psel- 

 aphidce, but with their elytra completely covering the abdomen (in 



