Article IV. — A List of the Insect Types in the Collections of the 

 Illinois State Natural History Survey and the University of Illinois. By 

 Theodore H. Prison, Illinois State Natural History Survey. 



Introduction 



The ever-increasing requests by technical workers in the field of 

 entomology for information concerning the insect types in the collections 

 of the Illinois State Natural History Survey and the University of Illi- 

 nois have led to the preparation of this paper. The reasons for such re- 

 quests are readily apparent to any one acquainted with the problems and 

 difficulties today confronting the scientific investigator in the fields of 

 taxonomy and nomenclature. The enormous number of insects already 

 described, comprising a total far in excess of the number of all other 

 known kinds of animals, is augmented each year by the recognition and 

 description of hundreds of species new to science. This multiplicity of 

 kinds of insects has greatly increased the difficulty of their classification 

 and brought to light many problems whose best solution rests upon a 

 restudy of the actual type specimens — the specimens used by the author 

 of a species in formulating the original description. 



Thus it happens that at the present time the types of insects have 

 come to possess a great practical value as well as a historical significance. 

 A complete realization of the value of exacting type-designations and the 

 proper labeling and preservation of the types did not come to most of 

 the earlier entomologists. In fact, it is only within comparatively recent 

 years that much emphasis has been placed upon exacting type-designa- 

 tions, disposition of types, full data concerning locality, date of capture 

 of specimens and the many other facts now commonly added to the orig- 

 inal description of a new species. 



It was but natural, then, that when the task was undertaken of list- 

 ing, locating, labeling and isolating the types in the collections here to 

 insure their safety, no uniformity of type designations was found in the 

 material. Various workers can be accredited for the numerous types, 

 some described at an early date and others comparatively recently. To 

 meet this situation the writer undertook the selection of lectotypes wher- 

 ever this was deemed necessary or advisable. This procedure is in line, 

 although not specifically covered, by that recommendation of the Interna- 

 tional Rules of Zoological Nomenclature suggesting that "only one speci- 

 men be designated and labeled as type". Furthermore, it makes paratypic 

 material available for exchange and for loan to specialists, as well as 

 eliminating certain undesirable situations that may arise from the ex- 

 changing of cotypes. 



