424 



difficult to cross; a single worker stationed itself there and undertook to help the 

 others over. It did this by taking part of the weight of the grain of corn and back- 

 ing across ahead of its companion until it had got it in a safe place. After helping 

 one it returned to meet another, and continued this a^jpareutly voluntary task as 

 long as this systematic robbery lasted. 



CICADA CHIMNEYS — CONTRADICTORY TESTIMONY. 



In a note upon page 276 of the current volume of Insect Life we 

 reviewed Mr. Benjamin Lander's theory as to the reason for " chimney 

 building" by the pupa of the periodical Cicada. Eecent correspond- 

 ence with Mr. Lander, and with Mr. J. G. Barlow, of Cadet, Mo., has 

 elicited some further observations made by these gentlemen, which are 

 so diverse in character as to leave the question as far from solution as 

 ever. 



The earlier supposition that these chimneys are built only upon low 

 ground has been shown by Lintner to be unjustified, and seems to be 

 further controverted by the observations of Mr. Lander, who has found 

 them in great numbers on top of the Palisades of the Hudson, and by 

 those of Mr. Barlow, who -writes that he has found them mostly on a 

 high ridge. Mr. Barlow also agrees with Mr. Lander in stating that 

 the chimneys occur in numbers where the undergrowth of saplings, etc., 

 is thick, thus contradicting another suggestion referred to in our former 

 note, that the chimneys are built to aflbrd the Cicada pupa an eminence 

 upon which to crawl while shedding its skin and unfolding its wings. 



Mr. Lander's observations tend to show that the chimneys are built 

 only where the soil is thin, covering a layer of rock or it may be a 

 stratum of sand too light to burrow in. Mr. Barlow, on the other hand, 

 reports finding the chimneys plentifully where the soil " was of reason- 

 able depth, with a foot or more of clay, then gravel below." 



Mr. Lander's theory of the chimneys is, in brief, as we understand it, 

 that owing to unusual warmth, either of the weather, as was the case in 

 March, 1894, or perhaps of forest fires, such Cicada pupae as are near the 

 surface of the ground are aroused to activity early in the season. "It 

 does not seem unlikely," he then says, "that the wonderful intelligence 

 of these marvelous creatures * * * would impel them to build 

 closed extensions to their short burrows as a protection from the pre- 

 mature heat * * * and possibly to shut out injurious intruders 

 during the incidentally lengthened period they would liave to wait for 

 full development over that of those who would later open their deeper 

 shafts, unroofed, at the surface of the ground." But both the objects 

 thus attributed by Mr. Lander to the Cicadas in building their chim- 

 neys are apparently contradicted b}^ the observations of Mr. Barlow, 

 who says, "I have seen the most of them where there was a layer of 

 dead leaves completely covering the chimneys from sight." 



These observations are so contradictory that it seems to us no definite 

 theory can yet be formulated as to the purpose served by the chimneys. 



