288 



SCIENCE. 



[Vol. XIX. No. 485 



and taken by myself, is Phlepsius humidus Van Duzee. 

 Though not uncommon, this species is recorded but once 

 outside of New York State, by two or three examples labeled 

 Delta R.E. I have taken it quite frequently, a ad Professor 

 Van Duzee says "it is not uncommon about Buffalo, in low, 

 swampy meadows and other humid situations." He has also 

 taken it near Lake Ontario, and states that this is tlie "' large 

 variety mentioned in his list of Hemiptera from that locality, 

 published in the Canadian Entomologist, for 1889. under the 

 name Allygus irroratus Say."' 



Jassus excultus Uhler is now to be known as Phlepsius 

 excultus Uhler. This species is well recorded from New 

 York, through Texas, to New Mexico. As yet I have not 

 Gollected this species, nor does Professor J. B. Smith, in his 

 "Catalogue of the Insects of New Jersey," record it from 

 that State. A thorough search will no doubt reveal its 

 whereaboufs in this locality also. 



Among the Jassidae collected by me in this locality, and 

 determined by Professor Van Duzee, is Cicadula S-notata. 

 It is very common and easily taken with a sweep-net. 



Jassus subfaciatus Say is also common, and Professor 

 Smith records t/assMS clittellarius Say, and Jassus irroratus, 

 DOW known as Phlepsius irroratus Say. Athysanus (gry- 

 poles) is represented in nay collection by four species, taken 

 here, tergatus Fitch, and unicolor Fitch, and two new spe- 

 cies named by Professor Van Duzee as Athysanus galbanatus 

 Van Duzee and Athysanus viridius Van Duzee. None of 

 the species are very abundant; and they are represented in 

 my collection by from three to six specimens, although the 

 former two species are much more abundant that the latter. 

 Professor Smith gives A. fenestratus Fitch, minor Fitch, 

 nigrinasi Fitch, variabilis'Eiich, striatidus Fallen, and uni- 

 color Fitch, as Jassus unicolor Fitch. No doubt all these 

 species are found here, and as far as Fitch's types are con- 

 cerned, we believe, belong to this State. 



In Deltocephalus I have collected inimicus Say, and Sayi 

 Fitch, both being quite rare as far as my collecting goes. 

 Professor Smith has inimicus Say recorded as Jassus inimi- 

 cus Say. Scaphaideus is represented by two species, one of 

 them new to science, and the other Scaphaideus immistus 

 Say. 



Athysanus is represented by Curtisii of Fitch, which is 

 not uncommon with me. 



In the subfamily TYPHLOCiBiNiE, we have Typhlocyba 

 roscB Fitch, and other species not yet determined, one species 

 being very common on Ptelea trifoliata, L, and of a deli- 

 cate green color. One of the undetermined species may be 

 trycincta of Fitch, and recorded by Professor Smith as oc- 

 curring in New Jersey. 



jErythroneura vitis Harris is common with us; but I have 

 not as yet found comes Say, or vulnerata Fitch, both found 

 and recorded from New Jersey, and the latter from New 

 York State also. 



In the genus Empoa, Professor Smith records guerci Fitch, 

 fabce Harris, and rosce Harris, the latter now known as 

 Typhlocyba rosce Fitch, as before noticed. 



Professor Smith also records Coelidea olitoria Say, and 

 C. subbifasciata Say. I have not as yet collected any of 

 this genus, although, in the present unsettled state of the 

 arrangement in several of the orders, it is quite impossible 

 to state just what one has, until such an arrangement as 

 Professor Van Duzee has given us with the genus Phlepsius 

 is worked out for all the families. 



It is to be hoped that hemipterists and all entomologists 

 will assist specialists by sending them specimens: and more 



accurate data should be given, with the material, than, I 

 must confess, I have been able to give in the past, so that 

 distribution and numbers may be determined. 



Edmund B. Sotjthwick, Ph.D. 



The Arsenal, Central Park, New York. 



LETTERS TO THE EDITOR. 



»•» Correspondents are requested to be as brief as possible. The writers namt 

 is in all cases required as proof of good faith. 



On request in advance, one hundred copies of the number containing his 

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The editor will be glad to publish any queries consonant with the character 

 of the journal. 



Readjustments of the Loup Rivers: Examples of Abstraction 

 Due to Unequal Declivities. 



Regeetting that my article on the " Evolution of the Loup 

 Rivers "' has been misunderstood, partly on account of an error in 

 drawing the map, I present herewith a corrected map (Fig. t), 

 showing the true location of the old channel connecting the head 

 of Wood River with the South Loup at Callaway, also some addi- 

 tional features not shown on the first map. 



In responding to the call of Professor Davis for " examples of the 

 lateral abstraction of one stream by another on a slope of plana- 

 tion," I must premise that planation is wholly distinct from ab- 

 straction. The efficient factor in the former process is latteral 

 corrosion, in the latter headwater erosion. Planation shifts one 

 stream bodily over to another, whereupon both unite in that chan- 

 nel, below the point of contact, which is the lower of the two. In 

 the process of abstraction the capturing stream does not itself shift 

 over to tlie captured stream, but exter\ds one of its tributaries 

 across the original divide by headwater erosion. 



Omitting, therefore, the phrase "on a slope of planation " from 

 the question as propounded by Professor Davis, I will say that the 

 phenomena in the Loup valley are such as to raise a strong pre- 

 sumption at least that some abstractions have occurred. As he 

 remarks, "the slopes are in the proper direction for such abstrac- 

 tion." Moreover, the old empty channels are there as silent wit- 

 nesses of adjustments already accomplished, and the ravines of 

 greater slope and more vigorous erosion, leading Into that stream 

 which lies at a lower level to the north-east, have already captured 

 much more than half of the space between streams, thus threaten- 

 ing further abstractions in the future. 



In addition to the one at the head of Wood River I would cite 

 as another example of abandoned channels the depression leading 

 up to the Dismal River in the line of Mud Creek, the approximate 

 position of which is roughly indicated by dotted lines, marked 

 " Old Channel " on the map. Mud Creek is a weak stream in a 

 great valley, itself as eloquent a witness of change as the dry 

 valley above. It must have carried a large volume of water, and 

 have been a worthy mate to the Middle Loup, before it was be- 

 headed by the Dismal, a vigorous tributary of its neighbor on the 

 north-east — the winning side in all these re-adjustments. 



To show the actual position of existing divides, as indicating 

 further abstractions, I have traced the water-shed by dotted lines 

 lor some distance between the North and Middle Loups, and be- 

 tween Cedar Creek and the North Loup and Calamus River. On 

 the latter line the distances are \Z^ miles from the divide to Cedar 

 Creek, and 4| miles to the Calamus. The eastward stream has 

 already captured three-fourths of the territory. On the former 

 line, at the south-east end, the divide is 12 miles from the North 

 Loup and 6i miles from the Middle Loup. Here two-thirds of 

 the divide yields allegiance to the eastward stream. At the 

 north-west end of the same line it wiU be observed that the water- 

 shed is nearer to the North Loup than the Middle Loup. This is 

 because the North Loup is a re-adjusted stream above the mouth 

 of the Calamus. If we measure from the latter, which is the true 

 original head of the North Loup, the divide assumes its normal 

 position nearer to the higher stream lying to the south-west. The 

 larger and longer stream, called the North Loup on account of its 

 size, is really an overgrown tributary, which owes its superior vigor 

 to the fact that it now flows more nearly in the line of maximum 

 gradient than does the Calamus, or the unadjusted North Loup 



