436 



Garden and Forest. 



[September ii, 1889. 



162. Genipa cLusi.aU'OLiA, Griseb. — This is a common, 

 littoral plant on several of the south Florida Keys. It 

 sho\vs, however, no tendency to become a tree or to grow 

 to a greater height than five or six feet, and should be 

 dropped, therefore, from the North American Silva. 



167. Arbutus Xalapensis, HBK. — Professor Gray, in his 

 supplement to the "Synoptical Flora of North America," 

 2 ed., ii. I, 396, proposed for this Arizona tree the name^. 

 Xalape7isis van Arizonica. It is not easy to connect this 

 plant, with its thick, white, scaly bark on the old trunks 

 and thin, narrow, glabrous leaves, with the Mexican A. 

 Xalapensis, which is known to me only through herbarium 

 specimens, and through the figure in Hooker's "Icones" 

 (t. 27) ; and it seems impossible to understand properly 

 either the Arizona or the Texas Arbutus without more de-. 

 tailed information with regard to the Mexican species of 

 this genus than is now available. 



168. Arbutus Texana, Buckley. — Professor Gray pro- 

 posed (/. c.) for this plant the name Arbutus Xalapensis, 

 var. Texana. It was believed formerly to be confined to 

 Texas, but two years ago I found a single plant on the 

 Sierra Madre, near Monterey, in Mexico, where Mr. Prin- 

 gle has since collected it. It may be expected, therefore, 

 to be a widely-distributed Mexican species at the northern 

 limits of its distribution in central Texas. The specimen 

 collected by Parry and Palmer (No. 562) near San Luis 

 Potosi, and referred to A. Xalapensis is certainly identical 

 with the Texas plant. C. S. Sargent. 



Entomological. 



The Periodical Cicada. 



A CORRESPONDENT in Essex County, New Jersey, writes 

 ■^"^ that when the seventeen-year Locusts visited his region 

 last he discovered that these insects were by no means as 

 harmless as they had been described. Farmers were assured 

 that they might prune orchards and forests a little, but would 

 inflict no serious loss ; but the fact was that many of the trees 

 in a young orchard, set out the year before, were killed out- 

 right, and most of the remainder were injured beyond re- 

 covery. He adds the common belief that some of this army 

 will appear a year or so ahead of schedule-time, and some 

 may follow later, but thinks the main host will appear in 1894, 

 and he adds that the years '92 and '93 will be dangerous sea- 

 sons for setting out young orchards. 



This letter expresses fairly well some of the beliefs on the 

 subject of this, perhaps the 'most interesting of American in- 

 sects. The fact that it appears every seventeen years is stoutly 

 maintained by some, and as stoutly denied by others. Cases 

 are cited of their appearing in the same localities at shorter 

 periods, while in other regions the seventeen-year record is 

 unbroken. To the scientific entomologist the problem has 

 long been a settled one ; but, somehow, the explanation has 

 not become generally known. As a matter of fact, instead of 

 one, or two, or three, broods, which are grudgingly admitted 

 as possible by ordinary observers, we know positively twenty- 

 two distinct broods, each brood with its own peculiar distri- 

 bution, and each of them well recorded for several periodic 

 appearances. Another fact not generally known is that in the 

 more southern regions eight of these broods have become ac- 

 celerated, from climatic causes, so that they appear at inter- 

 vals of thirteen, instead of seventeen, years. These broods 

 are just as true to their thirteen-year period as are the others 

 to their seventeen-year term. In some sections the two varie- 

 ties — for the thirteen-year brood is smaller than the other — 

 overlap, and sometimes it happens that a seventeen-year and 

 a thirteen-year brood will occur at the same time in the same 

 place, as in 1885 broods vii. and xxii. appeared together 

 along the Mississippi Valley. Of course, in such regions, 

 there will be a brood thirteen years from that time, and 

 another four years later. Such facts, incorrectly under- 

 stood, give rise to the popular ideas of an irregularity in ap- 

 pearance. So, also, where two, or even more, broods occur 

 in the same region, there will be an' apparent irregularity in 

 dates. This is instanced during the present year in Washing- 

 ton (brood viii.), where the cicada last appeared in 1885 (brood 

 xxii.), only four years ago. A very full account of all tiie 

 broods is given by Professor Riley in Bulletin 8 of the Division 

 of Entomology, United States Department of Agriculture, and 



a great deal of additional information in the report of the 

 United States Entomologist for 1885. 



New York is credited with six broods: 1889 [viii.], 1894 

 [xii.], 1898 [xvii.], 1899 [■''"'X.], 1900 [xx.] and 1902 [xxii.]. It will 

 be seen that for three years in succession some part of New 

 York will be visited by the cicada. 



New Jersey is cretlited with four broods : 1889 [viii.], 1894 

 ]xii.}, 1898 [xvii.] and 1902 [xxii.]. New York thus has all the 

 broods appearing in New Jersey, and, in addition, two others. 



The New Jersey broods do not overlap — /. e., there seem to 

 be no places covered by two broods, and I have therefore re- 

 ceived letters in abundance, and seen numerous notices in lo- 

 cal journals, denying the appearance of brood viii. this year. 



To be somewhat mOre specific, brood viii. (1889) has ap- 

 peared in Long Island, New Jersey, along the Atlantic Coast to 

 North Carolina and westward through Pennsylvania. The 

 brood becomes scattering and small in number along the 

 Atlantic Coast, and is very generally overlooked. In New Jer- 

 sey it appeared in small numbers at the Pahsades.at Princeton, 

 Palmyra, Red Bank, and for some little distance along the line 

 of the Cape IVIay Railroad. Mr. Angell, a very reliable ento- 

 mologist, assures me that he heard the insects at Orange, but 

 I received no specimens. Long Island is the only New Yoi'k 

 locality recorded. 



Without mentioning other broods, it only needs to be added 

 here that the largest of the seventeen-year race, brood xxii., 

 which covers the greatest territory and is also very niuneroiis, 

 does not appear here until 1902. In New York it appears only 

 on Long Island, extends in small detached areas through mid- 

 dle New Jersey, until, in Pennsylvania, the main army is 

 struck. It is somewhat doubtful whether the brood in 1902 

 will be very numerous on Long Island, for the sparrows 

 assembled in force in Prospect Park when the Cicadas ap- 

 peared, and spared very few indeed. So well was the work 

 done that in a search for eggs I spent an entire day along the 

 line of their appearance and found but a single punctured 

 twig ! 



Brood xii. (1894) appeared last in 1877 and is a very numerous 

 one. It extends along both sides of the Hudson as far north 

 as Troy, and crosses Long Island. They were in 1877 most 

 abundant on Staten Island, less so on Long Island, and I 

 observed them within the limits of New York City. In New 

 Jersey they were very abundant nearly all over the State, and 

 this brood is the one most generally remembered by farmers, 

 and to which most of the letters received refer. 



The larva of the Cicada lives underground and subsists by 

 puncturing the roots of trees and sucking their juices. The 

 rate of growth is so slow that the damage done is never per- 

 ceptible, and need scarcely be considered. The mature 

 insect takes its food in the same way, puncturing branches 

 only instead of roots, and its damage in this respect is very 

 small. The real injury is caused by the female in ovipositing. 

 For this she selects, preferably, the tender terminal shoots of 

 trees, shrubs, or, where they appear in large numbers, even 

 low bushes, and makes a series of deep longitudinal slits into 

 which the eggs are deposited. Where the twig or branch is 

 small, it soon loses vitality, and eventually dies. On large 

 trees this amounts to a severe pruning only ; but in small, 

 nursery trees or a young orchard, it frequently, if not generally, 

 means the death of the tree. The advice not to put out young 

 trees just before " Locust year," is sound. In New Jersey this 

 advice should be remembered for the 1894 brood, and so too 

 the farmers along the Hudson should take warning. This is 

 really the only brood occurring in damaging numbers in these 

 States. No practical remedies against these periodical pests 

 have been suggested. tv r> o • 7 



Rutgers College. J.B.Smith. 



Foreign Correspondence. 



London Letter. 



n^HERE are certain variegated and golden-leaved trees and 

 -*■ shrubs that display much beauty of foliage in spring and 

 early summer ; but, after exposure to strong sunshine, they are 

 often anything but beautiful ; indeed, nothing in a gai'den is 

 more unsightly than a tree or shrub with sunburnt foliage. 

 There is now such a great demand for these gold and silver 

 variegated trees and shrubs that every tree-nursery is crowded 

 with them, and the nurserymen are always alert to add some 

 novelty to their lists. In many cases I have asked for a 

 Catalpa, but was told it was not kept in stock, while I could have 

 any number of the golden-leaved variety. The same is ti^ue 

 of the beautiful pale-green Acer Negiindo. One who orders it 

 will probably get the variegated form, now too common 

 everywhere. There are many people who do not see the 



