Article II. — The Cyrus Thomas Collection of Aphididcc, and a 

 Tabulation of Species mentioned and described in his Publications. 

 By John J. Davis, B.S. 



Many inquiries, from specialists on the Aphididcc, and others, re- 

 garding the disposition and condition of the Thomas collection of 

 Aphididcc have Ijeen received, and the following data, most of which 

 are based on a study of this collection, seem worthy of publication. 



There are seventy-three slides and one hundred seventy-six vials 

 in this collection, all of which are in the custody of the Illinois State 

 Laboratory of Natural History. With few exceptions they are with- 

 out data other than numbers, the key to which is unknown. The 

 contents of many of the vials are dried up and the others are as a rule 

 in very poor condition, and the writer has not thought it worth the 

 time necessary to determine any of the species excepting those bear- 

 ing data other than the numbers. 



I am able to present these notes through the kindness of Dr. S. A. 

 Forbes, who has given me full access to the collection. I am also 

 under obligation to Mr. J. T. Monell, who kindly read and criticised 

 the manuscript. 



The three important contributions by Dr. Thomas on the Aphid- 

 idcc are the following. 



1877. Notes on the Plant-lice found in the United States. Trans. 111. State Hort. 

 Soc, 1876 (Vol. 10, n. s.), pp. 137-212. 4 figs. 



Chiefly a compiled paper, giving most of the older American descriptions. No 

 new species are described, but the name Eriosoma Rilcyi is proposed for E. 

 ulmi Riley, which name is preoccupied. At the close of the paper the plants 

 mentioned are listed with the aphids infesting each, as also the aphids men- 

 tioned with their plant hosts, and two synoptical tables are added, one giving 

 Passerini's arrangement of the Aphididce. 



1878. A list of the Species of the Tribe Aphidini, Family Aphidce, found in the 

 United States, which have been heretofore named, with Descriptions of some 

 New Species. Bull. 111. State Lab. Nat. Hist., Vol. I, No. 2, Art. I, pp. 3-16. 

 Printed in December, 1877, and separates distributed in January, 1878. 



Lists fifty-eight species of Aphididce, eighteen of which are described as new. 



1880. Eighth Report of the State Entomologist on the Noxious and Beneficial 

 Insects of Illinois. Trans. Dept. Agr. 111., 1878, Vol. 16, Appendix. 212-fX 

 pp., 47 figs. 

 On pages 46-172, author lists and gives descriptions of 149 species which occur or 

 are supposed to occur in the United States, seventeen of which are described as 

 new. As a supplement to his report he gives from the Riley-Monell paper 

 (Bull. U. S. Geol. Surv. Terr., Vol. V, No. i, 1879. PP. 1-32), as he says, "the 

 descriptions of the new species, and such observations and criticisms on their 

 [the authors'] notes as I think are required." 



