THE GENUS CORIZUS. 

 With a Review of the North and Middle American Species. 



By J. C. Hambleton. 

 INTRODUCTION AND ACKNOWLEDGMENTS. 



The writer wishes to express his sincere thanks to those who 

 have contributed to the success of this work by allowing him the 

 use of their collections. Among these should be mentioned first 

 Prof. Herbert Osborn whoallow^ed the use of his private collection 

 as well as that of the Ohio State University. Prof. Comstock 

 sent the collection belonging to Cornell University, and Mr. 

 Heidemann of the National Museum sent his private collection 

 of several hundred specimens. The collection belonging to the 

 Colorado Agricultural College was also at the writer's disposal. 

 Without this extensive material, it would have been impossible 

 to arrive at many definite conclusions concerning the genus. 



The first insect of this genus to be described w^as crassicornis. 

 Linneus in 1758 gave it a brief description and included it in his 

 large genus Cimex. Fabricius, in 1794, described two more 

 species, sidae and hyalinus, under the generic name of Lygaeus, 

 but later, in 1803, he changed them to the genus Coreus. In 

 18 1 4 Fallen created the genus Corizus and gave it the following 

 limitations: "Corpus oblongum; antennarum basali bre\i; ul- 

 timo subclavato; thorace planiusculo; hemelytris oblique trun- 

 catis; membrana longitudinaliter multinervosa." In 1828, in 

 his Hemiptera Sueciae, pages 41 to 45, he includes six species, 

 not all of which, however, have remained in this genus. The 

 only American species included here is crassicornis, a very com- 

 mon European insect. 



Signoret in 1859, in the Ann. Soc. Ent. Fr., published a mono- 

 graph of the genus. This is a notable work and has served as 

 the basis of nearly all the work that has been done on the genus 

 since his time. He recognized the practical impossibility of 

 separating the genus into natural groups, or subgenera. He 

 includes fifty-four species from all parts of the world, and des- 

 cribes many new American species, some of which have not with- 

 stood the test of time, probably because his material was not 

 abundant enough for him to understand their variations. 



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