IOWA ACADEMY OP SCIENCES. 
193 
The structural characters upon which the species have been 
founded have proved so constant, within measurable variations, 
for all the dilferent varieties, that I am confident the species 
and the synonymical determinations will stand. The limitation 
of sub-species and varieties, v^hile 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, Liiitner, Ashmead, Weed, Fernald, Goding, Skinner, 
VanDuzee, Sirrine, Maliy 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 ohtnsa. Say. 
Color markings of Sub-species I. ohtnsa. 
Showing color markings of faces. 
Figure 2. C. ohtusa-ohtusa. 
Figure 3. C. ohtusa-oshorni. 
Figure 4. C. obtusa-lineatocoUis. 
Figure 5. C. proteus-nigra (variety b.). 
Figure 6. C. pro tens Pitch. | 
Figure 7. C. xanthocephala Germ.* 
Figure 8. C. dclicata-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 Philsenus which either possesses two types or else there is 
another as yet unrecognized genus represented in our fauna. 
Figure I. Wings of Monecphora bicincta, Say. 
Figure II. Wings of Philsenus sp. 
Figure III. Lepyronia 4-angularis Say. 
Figure IV. Aphrophora quadrinotata, Say. 
Figure V. Philsenus sp. o 
I'igure 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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