lj(i 



Ililcii — Some litter relations of Plants and Insects 



tree Yucca, Yticca filifera, of noi'theasteru Mexico, reaching a 

 height of fifty feet, with its |)enchih^iis panicles five or six feet 

 h3ng, has a very elongate i)istil and comparatively short stamens. 

 The few pods which I have heen able to examine indicate the 

 presence of a Pronulia and doubtless of a distinct species which 

 will prove very interesting. Yucca, haccata, Y. trernlianen, and all 

 the species which are sufficiently distinctive^ in characters and in 

 range, may be expected to liave special Pronubas associated with 

 them. 



The Bogus Yucca iNIoTrr. 



An interesting fact connected with Pr(»nul)a and Yucca jiolli- 

 nation is that there is always associated with Pmrmbtt yiicra.-iella 

 another moth, which bears such a remarkalile su[)erficial resem- 

 blance to it, though possessing no power of pollination, that it 



bas caused much confusion in the 

 l)ast on the ])art of careless observers 

 and led to a good deal of misstate- 

 ment and error. This is wliat T have 

 called tbe Bogus Yucca Moth. Pro- 



r^ I 



(loxiis decipieitft (Fig. 10"). In size it 

 is somewhat smaller, on tlie average, 

 than Pronulta, and, while found as- 

 sociated with it, appears rather earlier. 

 The female has no maxillary tentacle, 

 l)Ut otherwise the genus has all tbe characteristics which would 

 place it in the same family as Pronuba. The ovipositor is a 

 stronger instrument (Fig. 

 11), but structurally ho- 

 mologous. The eggs arc 

 thrust into the stem while 

 yet tender ; they are elon- 

 gate in form, but short 

 and rounde(l at both 

 rwh^ resembling the un- 

 developed ova in the ova- 

 ries of Pronuba. Tbe 

 larva is absolutely a,])!)- 

 dous ( Fig. 12, o), forms its 

 cocoons within the stem, 

 and transfoniis the cnsu- 

 cnsuiii^ vcar to a cbi'vsalis, wbicb bas a miicli stronger capitate 



Fni. 10. — Prodoxus DEriPiKxs: a. 

 imago, wings closed; /;, femnU' im- 

 ago, wings e.xpanded — natnral size: 

 c, enlarged maxillary palpus witli 

 its liasal tnlierclc 



l''li. 11. — OkMTAI. rll.uiAl lERS OF PliODOXUS I)f:ClP- 



lEXs: a, tip of Q abdomen rendered somewhat trans- 

 parent: '), liasal joint of ovipositor : r, its seulptare : 

 r/, terminal joint of sann% its tip in<iri' cnlargi-d ; /', 

 genitalia o( 'S^ from side: ty, do IVum alMJVc; /(, egg. 



