22 



Big Horn and Little Big Horn Kivers in Montana ; by pulling off the bark of the dead 

 trees they would be found in numbers. The question occurred to me " what they 

 lived on ; " they were not dull, but perfectly lively as soon as exposed to the light. — 

 [S. M. Swigert, captain, Second Cavalry, U.S. Army, Fort Leavenworth, Kans., May 

 10, 1890. 



llEPi.y. — Your letter of May 10 has just come to hand. I have known for some time 

 that the domestic Bed-bug will live for a longtime, even for years, iu locations where 

 buildings have once stood or in spots where there have been camps iu the woods. 

 But if; seema more likely to me that the insect which you have found under the bark 

 of the Cotton-wood is not the true Bed-bug, but that it is another quite similar bug of 

 the genus Aradus, the species of which are often found in such localities, and which, 

 before they have attained their full size, strongly resemble the Bed-bug. I can settle 

 this point for you if you will take the trouble to send iu specimens — [May 13, 1890. ] 



The Orchid Isosoma again. 



Since the receipt of your letter, etc., concerning the Orchid Isosoma, about which 

 I made inquiries last fall, I have endeavored to make observations and obtain more 

 material, but, owing to the previous vigilance of the florist who was troubled by it, I 

 have not been able to do so. He has given me, however, a number of roots of Cattleya 

 gigas affected with galls containing, I think, dipterous larvte. Those I have opened 

 cout ined from one to seven maggots, separated from each other by the substance of 

 the root. I inclose some for your inspection. As you will see, the galls are situated 

 near the tips of the roots. The trouble seems to have been introduced on a plant 

 from England last year, and to have spread to a few plants hanging nearest that one. 

 Owing to the costly character of the plants affected by this pest as well as the Iso- 

 soma, all insects attacking them are destroyed as soon as discovered, but I am trying 

 to obtain as much material as possible. — [Albert P. Morse, South Natick, Mass., May 

 8, 1890. 



Reply. — Yours of the 8th instant, with maggots found in galls on roots of Cattleya 

 gigas, has been received. These are the larvte of a species of Cecidomyia, or of the 

 allied genus Diplosis. I can tell you nothing more until the adult flies are reared. 

 As you will notice in my note in Insect Life, copy of which I sent you some time 

 since, some skepticism exists among English entomologists for the very reason that 

 Dipterous galls occur upon these Orchids, and the Isosoinas have been considered by 

 them as their guest flies or parasites. This, moreover, would be strengthened by the 

 fact that we can unquestionably separate 7. orchidearum from the restricted geuus 

 Isosoma, which is composed entirely of phytophagic species, were it not for the fact, 

 as I also state upon page 121 of Vol. I of Insect Life, that the larva) have been 

 watched by me in all stages and observed to feed upon the orchid substance, and 

 that the cavity made at first is only just large enough to contain it aud its frass, I 

 am glad that you are int resting yourself in this matter, and hope that you will in- 

 dicate your further observations to me for the benefit of the readers of Insect Life. — 

 [May 12,1890.] 



Eristalis in Well Water. 



I send by mail to-day a specimen of a small worm that infests a well at this place. 

 Ordinary cleaning of the well does not get rid of them, but they quickly redevelop, 

 80 that one bucket of water will frequently contain three or four. As a matter of 

 course the water is not used for drinking purposes, but the proprietor would like to 

 use it and be freed from these pests. — [Dr. D. B. Frontis, Johnston, Edgefield County, 

 S. C, May 7, 1890. 



Reply. — The maggots which are infesting the well in your town are those of a 

 Syrphid fly of the geuus Eristalis and probably belong to the species known as E. 

 tenax. These larva>, together with those of several allied genera, have h)ng been 

 known to live in decaying vegetable matter, in manure, or in soft mud impregnated 



