■200 



rsrcHE. 



Aiiijusl — Septeniher iSJv^. 



a large numljcr (if specimens from ilit- 

 ferent parts of the countrv. and \villi(iiit 

 exception have denuinstrated their com- 

 posite nature. 



This compmnul character of Uie ;j;alls 

 implies a clf)se interdependence between 

 the fungus and insect. That lilivtisiiia 

 solldagtJiis or R. asteris cannot occur 

 without the presence of Cecidomvia 

 carbonifera. or vice versa, cannot be 

 said ; vet I have ne\er seen one without 

 the other. Onlv a study of the ilevelop- 

 ment of the galls can show wliether tlie 

 insect paves the vvav for the fungus or 

 lives onlj' in leaves previouslv attacked 

 bv the latter ; but the great powers of 

 multiplication and dissemination pos- 

 sessed bv most fungi incline me to tile 

 belief that the former is the case, the 

 mvcelium being unable to penetrate the 

 uninjured plant, as Hartig has shown to 



be tile case with parasitic species of 

 Xeclria. etc. From the carbonization 

 of all the species i^i lihvti^nia . it is prob- 

 alile that the color of the galls in the 

 present instance is due to the fungus. 



The form of fiiiit of the Rlivtisma. 

 and the earh development of the galls, 

 coultl be easil\ made out liv anv collect- 

 ing entomologist or botanist living in the 

 eastern states, where the\' occur : and as 

 I no longer ha\e access to good material 

 these notes aie published in their pres- 

 ent incomplete foim to draw attention to 

 a verv interesting subject for further 

 study.' 



' Sections of an undetermined cecidoinvid j;ull on 

 Impatient ftilva^ from Medford, Mass., prepared in my 

 lab;iratorv bv Miss L. N. Martin, show a mycelium 

 soniewliat similar to that noticed in Astfr and Sotidago 

 leaves, and there is also a certain amount of cjlrboniza- 

 tion. It will be interesting to observe whether the 

 mycelium is always present in this tjall which is not 

 vmcommon. 



WANT OY .SYMMETRY AMOXc; INSECTS. 



BV OSKAR PACI. KK A NC'll Kl! . LEIPZIG. (iKKMANY. 



The extraordinary svmnielrv which 

 occurs among insects is usuallv liroughl 

 prominently forward in most of tlie 

 books which treat of entomologv. Xolh- 

 ing is pictured more svmmetricalb' than, 

 for instance, the structures of bees ami 

 ants, or the color of butterflies, which 

 latter is prominentlv reputed to have a 

 perfectly symmetrical bilateral e(jnalit\'. 

 Although there is much truth at the bot- 

 tom of all this, although nature in main 

 cases works with great s\inmctr\. \ct 

 it must not he overlooked that even this 

 s\nimetrv is often converted into its 



strict opposite. Siu'elv no observing 

 lepidopterologist has. failed to notice 

 that the coloiation of tlie wings of his 

 favorites is to be recogni/ed as stiictlv 

 svmmetrical oiiK in the smallest num- 

 ber of cases, that, indeeil. that of one 

 side, which certainlv lesenibles that of 

 the other in its superlicial aspect, still 

 shows main ditl'erences in its details, 

 and there is little foundation for assert- 

 ing that the\ are s\ mmetrical. I might 

 cite innunicrable examples of this, but 

 the reader can better see them for him- 

 self. This is most plaiiiK shown in tiie 



