142 SUMMARY OF CURRENT RESEARCHES RELATING TO 



species of Myrmecocystus, il seems that there are "recognition-points" 

 distributed around the nest at a distance of 9 or 10 metres. These 

 points arc isolated, and there is something about them that evokes 

 re-orientation. They may be points from which some finger-posl 

 ass iciated with the still distant nest is perceived. J>ut the difficulty is 

 to discover how these points differ from others close beside them. In 

 species of Messor, there was no evidence of any acquired knowledge of 

 the region around the nest. Transported from near the nest to a 

 distance of a yard they behaved as if in an unknown world. The theory 

 t iat a, Ms at a distance from the nest make use of the differential 

 illumination of objects near the nest, requires to be carefully tested. 

 Many ants have a very short range of direct perception, and their 

 horizon is very near at hand. That some perceive big differences in 

 distant illumination has been satisfactorily proved. Cornetz was led 

 by these prohlenis to make some observations in darkness. 



When a track of Tapinoma, marked by odoriferous traces, is inter- 

 rupted and washed across for 20 cm., it is restored in 15-20 minutes. 

 The restoration begins by an ant crossing the gap in a definite and 

 right direction, and in a confident manner. Is this because of an 

 orientation in reference to the light in the sky ? Cornetz covered a 

 gap of 40 cm. with an op.ique sheet, and found that no ant got across. 

 But when he put the sheet over an uninterrupted march, he found that 

 the inarch stopped. The stoppage is induced by the sudden cooling of 

 the earth and the abrupt change from light to darkness. When the 

 experiment was made in the twilight there was no stoppage, only a 

 retardation and an interrupted march was reconstituted. 



Daring the night Cornetz observed a track of Tapinomit, with 

 110 to 1G() ants to 1 m., which extended between two houses for 18 to 

 20 metres. He made a gap of 3 to 4 m. and washed it. For three 

 minutes there was a block at each side. Then a worker went straight 

 across (as was seen by means of a dark lantern) and the march was 

 restored in 15 to 18 minutes. The next evening he repeated the experi 

 ment, but covered the gap with a long wooden form, which shut out 

 the stars (Cassiopeia). It made no difference to the result. Cornetz 

 believes in a sense of direction to this extent, that these ants are able to 

 go right on in the path which they were pursuing, though all the scent 

 traces have been washed away, and though there is no illumination. He 

 cannot defend his conclusion logically, but he is forced to a belief in 

 the ant's memory of the position of the median plane of its body in 

 space, and in a memory of the " direction " in which it was going. 



New Miocene Coleoptera from Florissant.* - - H. F. Wickham 

 reports on part of a rich collection of beetles from the Florissant Shales. 

 Scudder began the study in 1893 and described 210 species ; Cockered 

 and Beutemueller have described 6 ; Wickham has described 172 new 

 forms. The present paper includes 86 of these. It seems to be plain 

 that the proportional development of the various coleopterous families 

 during the Miocene times differed, sometimes very decidedly, from that 

 obtaining to-day. 



* Bull. Mus. Comp. Zool. Harvard, Iviii. (1914) pp. 423-94 (16 pis.). 



