Insects in On hid Houses. 1 09 



bom's ciUTot-l)i'(l ; every cnrr<»t luus l»een ruiiie«l ; his IkkI is ullerly 

 iiiineil." To^'elher with the work of the Carrot Fly in this nci<i;h- 

 l>oiirho(.Kl wa.s u had attack of Aphis. " People ahout heiv," writes 

 Mr. llaininniul. " aix* complaining that their carrots are very much 

 infested with A])hides at the routs." This wils early in Octolier. 

 IJv the 2<tlh Mr. Hammond found that thev had nearly all dis- 

 apj)earetl. Thiy are to Ik? found "generally on the crown of the 

 carrot; they do not cause the cmcks, hut shelter in them. The.se 

 Ajdiides wei-e too shrivelled to identify when they anived ; they 

 weiv ])rohably Srhizoncitra foilicns. 



Correspondence and Report on Insects in Orchid 



Houses. 



Gatton Pauk, Surrey, 



Wi July, 1902. 



To Professor E. K.^y L.knkkstkh, ^I.A., etc.. 



Natural History iluseum, South Ken.sington, S.W. 



My Dk.vu Sir, — I am a collector of oifhids and somewhat lar^'dy 

 intcrestctl in their hvhridization, hut our efforts are matcriailv interfi-n-d 

 with by a little Hy or its grub (specimens of which I enclose), and whose 

 rava;_'es we liave f<»niul no means of jirev«ntin<r. It is no uncommon 

 thing for them to dear off the whole of the contents of a pit of seed iis 

 soon iis it is sown and germinates. We have made the following oljserva- 

 tions in regard to it : — 



They seem to frcipient and tiirive most where they have damp moss to 

 dwell in, which unfortunately is an es.scuiial feature of succe.-vsful orchid 

 growing. 



Iking ofun fnund on plants that have no seed on them, tluy of course 

 have other food, l»ut apparently they have lar^aly increased in my hou.ses, 

 A hich, however, may be due rather to the amount of moist moR.s al)0ut than 

 to the amount of orchid seed which they have to feed on. They are 

 C(pially troublesome in what we know as the "Cool Hcmse" (.*iO to ilo'^ F.) 

 ;is in the hot ones (<;.'» to x'>' F.). They devour the seed immediately it 

 connnences to germinate, and if not devoured in this stiige they attack 

 the small bulbh-t liS soon as it is fonnetl, eating it from the base and 

 leaving the shell only. They are harudi-ss to ])lant8 after the early stages 

 and m> are not troublesome to orchid growers generallv. 



Careful search \u\s failed to discover a yrub. llence it is assiuued 

 (iH>sibly erroneously) that it is the fly which d(»cs the mis<hicf. Further, 

 llie winged one (r male) is rarely found on the j>ot*, which leads to the 

 iLssumption that it is the wingless one which i\ow the mischief. If we are 

 wrong in the assumpticui that tli<' ma|i,' only has wings our id>scrvation 

 woidd leml to the siiggestion that the fly is harmful only before it develojw 

 its wings. The body of the wingless one on the \HtUi is much larger than 

 the one ft»und with wim.'s. When the seed is sown on a flat surface 

 without harbour we are not iroulikd ; but din-dly tin- seetl is remove<l, 

 which it has to be sotm aft- r ■'••rmimition if \<, , ,.111, ^ litM.- to attjtck. 



