IOWA ACADEMY OF SCIENCES. 193 



The structural characters upon which the species have been 

 founded have proved so constant, within measurable variations, 

 for all the different varieties, that I am confident the species 

 and the synonymical determinations will stand. The limitation 

 of sub-species and varieties, while as accurate and complete as 

 the 400 specimens of available material would allow, will doubt- 

 less undergo some expansion and correction with the accumula- 

 tion of new and larger collections of material. 



In conclusion I wish to acknowledge indebtedness to Messrs. 

 Gillette, Lintner, Ashmead, Weed, Fernald, Goding, Skinner, 

 VanDuzee, Sirrine, Mally and Gossard and Miss Beach for the 

 privilege of examining material, and for other favors extended, 

 and to Professor Osborn, in particular, for the use of his pri- 

 vate collection and the department material, and for his invalu- 

 able counsel and advice.* 



EXPLANATION OP PLATES. 



PLATE XI. 



Figure 1. Clastoptera obtasa, Say. 



Color markings of Sub-species I. obtusa. 



Showing color markings of faces. 

 •^ Figure 2. C. ohtusa-ohtusa. 

 C Figure 3. C. obtusa-oshorni. 

 C" Figure 4. C. obtusa-liaeatocoUis. 

 O Figure 5. C proteus-nigra (variety b.). 

 O Figure 6. C. pro tens Fitch. ; 

 O Figure 7. C. A-antAocepAa/a Germ.' 

 O Figure 8. C. delicata-lineata (variety a.). 



PLATE XII. 



Venation of upper and under wings represented by one species from 

 each genus as a type. The venation seems to be very constant within 

 generic limits, as far as I have had opportunity to examine, with the 

 exception of Philxaus which either possesses two types or else there is 

 another as yet unrecognized genus represented in our fauna. 

 G Figure I. Wings of Monecpbora bicincta, Say. 

 C Figure II. Wings of Pbilsenus sp. 

 <3 Figure III. Lepyronia 4-angularis Say. 

 Figure IV. Apbrophora quadrinotata, Say. 

 Figure V. Pbilsenus sp. o 

 C Figure VI. Clastoptera obtusa, Say. 



* This work has been done in the entomological laboratory of the Iowa Agricul- 

 tural College, and submitted as a graduating thesis. 

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