no First Report on Economic Zoology. 



Yarious methods have been unsuccessfully tried, particularly the 

 following : — 



Fumigation, either with tobacco or a compound known as " X.L. All " 

 (this is supposed to contain nicotine, camphor, methylated spirits, etc.), 

 but neither has any material effect. Quassia affects them only for a short 

 time, as they leave the pots and return in a few days. The pots have been 

 placed under water for hours, but upon being taken out the flies are equally 

 as lively as before. Fly-paper and strings similarly covered are of no avail. 



(X.B. — The houses are regularly fumigated for pests, in general about 

 every ten days.) 



I should be very glad to know if there is any method of ridding 

 ourselves of the pest by destruction or of making it harmless to the 

 germinating seed and bulblet by driving it from the pot or otherwise. 

 Any information as to its known habits might help us to w^ork out its 

 destruction if no remedy is known. It is of course important that any 

 remedy shall be harmless to the orchid seedlings themselves. They are 

 extremely delicate and porous and have to be kept in a constant state of 

 moisture. 



I must apologise for having troubled you with so long a letter, but the 

 ravages of this insect are most annoying and often rob us of results which 

 have promised to be of great interest in the horticultural world, and I 

 should feel much indebted if you could let me know of a remedy or of any 

 one who would be likely to advise me should you personally be not 

 acquainted with one. 



I beg to remain, etc., 



(Signed) Jeeemiah Colman. 



Report on Insects in Orchid Houses. 



The insects sent by Mr. Colman, of Gatton Park, Surrey, causing 

 harm to orchids, are in too broken a condition to identify accurately. The 

 small flies are Sciarime, and belong to the genus ZygonBura, of which only 

 one species occurs in Britain — Z. sciarina (Meigen), found in summer and 

 autumn in underwoods and moss — but without seeing fresh and perfect 

 specimens it is not possible to be certain of the species. The life-history 

 is not known, but probably they breed in the damp moss. The larvae do 

 not seem to have been observed ; they would possibly be in the form of 

 small white footless grubs. 



The flies can do no harm — it would be the larvje — but there is no 

 doubt that the damage is done to the orchids by the wingless creatures 

 sent at the same time. There is no connection between the wingless 

 insects and the Sciarinie. The wingless forms are CoUembola, or Spring- 

 tails. Some of these are certainly very injurious, but little is known of 

 them, however. The young of these Spring-tails resemble very closely the 

 adult, and live and grow in similar situations and under similar conditions 

 and are injurious during the whole of their existence. Preparations have 

 been made of this Collembola, and attempts will be made at its 

 identification. 



The majority of species live under damp moss and stones and are no 

 doubt encouraged by the methods necessary in orchid cultivation. All 

 that can be suggested is that Mr. Colman experiments on a small scale 



