316 



either there is no body left, only a ghost, which has no anatomy. I hope you appre- 

 ciate my scientific knowledge. 



The other goes popularly by the name of " sih^er fish.'' It also is a creature of the 

 damp. The colored people declare it is the husband of the moth. I killed one in May 

 that looked formidable for it was more than two inches long. When I returned this 

 autumn a bit of flannel that had been carelessly left out was riddled with moths, and 

 as I took it up to throw it in the fire a very large " silver fish " slipped out to meet a 

 speedy doom. Such is the origin of the myth, I suppose. Now, can you refer me to 

 any Government bulletin which will give me the biography of these unwelcome vis- 

 itors, or any book? If not, will you give me some of the facts yourself and introduce 

 me to the husbands and wives, if they do not have a family likeness. — [Caroline H. 

 Dall, No. 1603 O Street, Washington, D. C, November 12, 1889. 



Reply. — Your letter of the 12th inst. was duly received, and while it would have 

 been desirable to have received specimens of the "creatures" to which you refer, 

 your interesting description of them leaveslittle doubt as to their identity. The one 

 which you call a centipede — and it is one — has no definite common name other than 

 "Thousand-legs," or the more inaccurate "ear-wig," but is known to science as Cermatia 

 forceps. The two sorts observed by you were only different phases of the same ani- 

 mal, the tangle being either a dead specimen or the exuvium (for, like all Arthropods, 

 it molts). Little is known of the habits or life-history of this widely distributed pest, 

 which of late years, particularly, has frequently occasioned annoyance in houses. 

 It is undoubtedly carnivorous in habit, however, probably feeding on other house- 

 hold pests, which its quick movements enable it to capture. There is current belief, 

 well founded, I think, that it feeds on young roaches. Its bite, while reputed poison- 

 ous, is not dangerously so; and I have personally never known of injury so resulting 

 and much doubt if there is foundation for the belief. It may, however, be considered 

 as a friend, but its singular appearance and rapid movement are hardly calculated to 

 inspire confidence. 



The " silver fish " of your letter is without doubt the well-known pest of books 

 and clothing {Lepisrna saccharina), and is entirely distinct from the clothes moths. It 

 feeds particularly on starched clothes and the binding of books, which it eats for the 

 starch, and sometimes injures silks and other fabrics. Pyrethrum will prove effective, 

 also, against this last insect. I am sorry to say that there are no publications of the 

 Department relating to these pests for distribution. The first is fully described by 

 Dr. Lintner in his fourth report on the insects of New York, and the second is briefly 

 described in Packard's " Guide to the Study of Insects," p. 623. — [November 13, 1889.] 



A Guava Scale. 



I send you a branch of guava tree, the first and only one that I have ever seen in- 

 fested with any kind of an insect enemy. I suppose this to have come from a large 

 rubber tree near by. The rubber tree is often covered with this black dust and same 

 kind of a scale. Will you please tell me the name of this creature, and whether it 

 will be likely to spread to other guava trees ; and if so, how can we best dispose of 

 it.— [E. Gale, Lake Worth, Dade County, Fla., November 13, 1889.] 



Reply. — The specimens which you send from guava are common Florida wax-scales 

 {Ceroplastes floridetisis). You will find this insect figured and described in Hubbard's 

 Insects affecting the Orange. It commonly affects the gall-berry, but is also found 

 upon quince, apple, and pear, and occasionally upon orange. It can be destroyed 

 by the ordinary kerosene soap emulsion, which, however, should preferably be ap- 

 plied when the insects are young. — [November 20, 1889.] 



The Tile-horn Borer. 



Last year I sent you specimens of borers which were destroying an ash tree in ray 

 yard, and worms also found in a large oak in the same yard. The ash tree died. By 

 this mail I send yon another specimen of borer, found in the heart of a large oak 



