632 



SCIENCE 



[N. S. Vol. XXXIII. No. 849 



cially the carabid beetle Orihogonius acutang- 

 ulus, the swollen or " physogastric " larvae of 

 which feed on the termites. Wasmann had 

 supposed that these larvae were adopted and 

 fed by the termites in the place of their own 

 huge queens, but Escherich shows that there 

 is nothing to support this view. The first 

 chapter of the book concludes with an account 

 of the growth of termitaria and the architec- 

 tural instincts of the worker and soldier 

 termites. 



The second chapter is devoted to the habits 

 of the species of Eutermes, which have pecul- 

 iar nasute soldiers, and especially to a charm- 

 ing account of E. monoceros, a black termite 

 which goes forth in long processions fully ex- 

 posed to the tropical sun to browse on the lich- 

 ens on tree-trunks and the roofs and walls of 

 houses. These processions are indeed " er- 

 staunlich," since they may be several hundred 

 meters long and make the most unaccountable 

 detours, " often three and four times the short- 

 est distance to the feeding grounds." Esch- 

 erich estimates the number of individuals in a 

 colony of this species at about 200,000. It re- 

 minds one of a common European ant, Lasius 

 fuliginosus, not only in its dark color and its 

 tendency to form these long processions, but 

 also in its nesting habits. Its termitarium is 

 a carton structure and, like that of L. fuligi- 

 nosus, situated in a hollow tree-trunk. Esch- 

 erich finds that it also forms on the outside of 

 the trunk an " Abtritt," or latrine near its 

 nest, a black stalactite-like mass which grows 

 gradually as the workers add their feces to it 

 and eventually drops from the tree or dis- 

 solves away in the tropical rains. It is, how- 

 ever, constantly renewed and is guarded by a 

 cordon of soldiers called by Escherich guards 

 of the latrine (" Abtrittswachter ")• Since 

 the workers and soldiers of E. monoceros are 

 blind, Escherich was naturally led to investi- 

 gate their " homing " instincts. Bugnion, 

 who had previously studied this same termite 

 in the same locality, showed that its sense of 

 smell is very acute, and Escherich finds that 

 the workers while they move along discharge 

 from time to time small, black fecal masses 

 which adhere firmly to the substratum like so 



many fly-specks and serve as guide-posts for 

 the workers and soldiers that follow. He con- 

 cludes, therefore, that the " spoors of the black 

 termites not only have a more intense odor 

 than those laid down by the ants, but are 

 much more stable and persistent." A brief ac- 

 count is added of the habits of some other 

 species of Eutermes and especially of the 

 "gallery" termite {E, ceylonicus), which, like 

 most species of the genus, constructs a gal- 

 lery or arcade under cover of which it moves 

 from place to place. 



The third chapter is full of interesting mis- 

 cellaneous observations and accounts of labo- 

 ratory experiments. It opens with some re- 

 markable notes on the queen termite and 

 contains confirmation of Holmgren's recently 

 published theory according to which the queen 

 termite sweats out on to the surface of her 

 body a substance (" exudate ") which is 

 eagerly devoured by the workers and not only 

 keeps the helpless queen supplied with at- 

 tendants, but, so to speak, binds the whole 

 colony together. Not only are the attendant 

 workers continually licking the body of the 

 queen, but Escherich actually saw a worker 

 tear a strap-like piece out of its mother's hide 

 and lap up the liquid exuding from the wound. 

 He noticed also that the unwieldy bodies of 

 the queens are often scarred in such a manner 

 as to suggest that this treatment is not un- 

 usual. The exudate thus obtained by licking 

 or even wounding the queen is often distrib- 

 uted to other workers by regurgitation. From 

 these and many other observations Escherich 

 infers " that the eager licking of the queen 

 has its origin not only in the cleansing in- 

 stinct of the workers, but quite as much in 

 their feeding instincts, or, ag Holmgren says, 

 in their ' exudate-hunger.' " The queen 

 termite is therefore fed and cherished by her 

 ofl^spring as if she were herself a termitophile, 

 or termite guest, and for the same reasons, 

 and since the other castes — i. e., the males, 

 workers and soldiers and their larvae — also 

 have exudate organs of peculiar structure, 

 Holmgren assumes that the whole problem of 

 caste difl'erentiation in these insects is to be 

 solved with the aid of the exudate theory. In 



