September 25, 1885.] 



SCIENCE, 



265 



expires." Dr. Fitch cits as to the length of 

 its duration ; and I have also erred in the same 

 direction — unless, indeed, there is a still greater 

 range than ni}^ subsequent observations would 

 indicate.-^ It is more probable, however, that 

 our memories were at fault ; for, as I have 

 verified this year, this shrilling ordinarily lasts 

 from two to three seconds, though occasionally 

 longer, and is repeated at intervals of every 

 five seconds. This note is rarely made by 

 solitary males, or when but few are gathered 

 together : but it is the prevailing note in the 

 height of the season, and is made in unison ; 

 i.e., the assembled males on a given tree, or 

 within a given grove, are prompted to it simul- 

 taneously, so that its intensit}' becomes almost 

 deafening at times. It is of the same nature 

 as that made b}' the dog-day Cicada (Cicada 

 pruinosa Sa}'), and in its higher and louder 

 soundings is not unlike the shrilling of that 

 species, though by no means so sharp and con- 

 tinuous. It is what in the distance gives the 

 threshing-machine sound, and it has often 

 recalled what I have heard in a saw-mill 

 when a log is being cut crosswise b}^ a circular 

 saw. 



Third, There is what maj' be called the 

 intermittent, chirping sound, which consists of 

 a series of from fifteen to thirty, but usually 

 about twenty- two, sharp notes, sometimes 

 double, lasting in the aggregate about five 

 seconds. This sound is so much like that 

 ordinarily produced b}' the barn or chimney 

 swallow (Hirundo erythrogaster) , that a de- 

 scription of the one would answer fairlj- well for 

 both. It resembles also, though clearer and of 

 higher pitch, the note of Microcentrum re- 

 tinerve Burm., which I have likened to the 

 slow turning of a child's wooden rattle highly 

 pitched. The above notes, so far as I have 

 recognized them, are of higher pitch, but 

 of less volume, in the smaller, Cassinii, 

 form. 



The other notes — viz., that made when the 

 insect is disturbed, and a not infrequent short 

 cry, that may be likened to that of a chick — are 

 comparatively^ unimportant : but no one could 

 do justice to the notes of this insect without 

 embracing the three peculiar sounds which I 

 have attempted to describe above, and which 

 are commingled in the woods where the spe- 

 cies is at ail common ; though the undulatory 

 screech is by far the most intense, and most 

 likelv to be remembered. 



C. V. Riley. 



1 Since this was written, I have heard, on two occasions, this 

 note prolongKi to twenty seconds; but this is quite abnormal, 

 and 1 have no other evidence than the season (June 20) to prove 

 that it came from C. septendecim. 



LOST RIVERS. 



The phenomenon of a stream flowing mer- 

 rily down from a mountain and then disap- 

 pearing, is, in the west, a very common one. 

 In following down the Rio Grande on an en- 

 larged map, we find many streams entering 

 into it in its upper course. In going down 

 a little farther, reaching the San Luis vallej', 

 thc}^ are found to suddenh^ give out on the 

 northern side ; and, a few miles farther down, 

 on the southern side also. The principal 

 streams of the valley, the Rio Grande excepted, 

 come in full force down the mountain, flow 

 freely on, and terminate in a marsh, or a small 

 lake, or in the sand. The beds of those which 

 should empty into the Rio Grande are there, 

 but there is no water in them. Similar streams 

 are common over the south-west ; and the 

 various streams show all the different stages, 

 from those which reallj^ go somewhere all the 

 time, to those which empty into their main 

 stream a part of the time, and those which, 

 alive and full of water above, always fail to 

 reach the stream to which they are headed 

 below. 



One time I had the curiosity to examine a 

 stream at the point where it was lost. It was 

 the Rio Hondo, just south of Santa Fe. We 

 had crossed it lower down ; and, though the 

 ravine was seventy-five or a hundred feet 

 deep, we had found it perfectly dry. We fol- 

 lowed up its south bank for a mile or two until 

 we struck the foot-hills, and there we found it 

 a bright, rippling stream, leaping down from 

 ledge to ledge, ver^^ picturesque, with some 

 scattered trees along the banks, and so broad 

 that it was not easj^ to pass over it, leaping from 

 stone to stone, and remain dr3'-shod. From 

 here my friend drove back to the crossing, 

 and I walked down to see where and how a 

 stream could lose itself with such a volume of 

 water, and a path well marked out for it. As 

 I followed it down, it ran on merrily in the 

 midst of a little valley not more than six or 

 eight rods wide, along which were pretty mead- 

 ows alternating with clumps of bushes. It 

 passed through the various incidents of a 

 stream, — here a little fall, there a rapid over 

 thickly set stones, a little farther on a pool. 

 There seemed to be nothing unusual in it, when 

 suddenh' I noticed that the little valle}^ widened 

 to double its previous width, the bed became 

 more sand}', and the stream was spread over a 

 greater space. It was evidenth' going under ; 

 and, within twent}' rods of where I noticed the 

 first change, the running water had entirely 

 disappeared. The bed of the stream was damp 



