214 IOWA ACADEMY OF SCIENCES. 



CONTRIBUTIONS TO A KNOWLEDGE OF THE THRIP- 

 ID^ OP IOWA. 



ALICE M. BEACH. 



This paper represents the results of a study of some of the 

 Thripidag of Iowa, and is based upon an examination of mate- 

 rial found in the collection of the Iowa Agricultural College, 

 some specimens kindly loaned by Miss Emma Sirrine, Messrs. 

 F. A. Sirrine and C. W. Mally, and some in the writer's own 

 collection. Descriptions of seven new species and three new 

 varieties are herewith presented, including a new species of 

 Phloeothrips described by Prof. Herbert Osborn. The descrip- 

 tions are preceded by an artificial key, arranged to aid in the 

 identification of all the described Iowa species known to the 

 author. The table for the determination of genera is substan- 

 tially that found in Comstock's Introduction to Entomology, 

 pp. 125-127. The writer is indebted to Mr. Pergande for an 

 outline of the characters of Euthrips, and is under special obli- 

 gations to Professor Osborn for valuable aid in the prosecution 

 of this work which has been done in the Entomological Depart- 

 ment of the Iowa Agricultural College. 



TABLE FOR DETERMINATION OF GENERA. 



A. Last abdominal segment in both sexes elongated, narrow, tubular; 

 both pairs of wings similar, veinless, margins equally ciliated; 



maxillary palpi two-jointed; borer in female absent. -. 



Sub-Order I. Tubulifera. 



B. Contains but a single family Fam. I. Tubuliferidse. 



C. Contains but a single genus. Gen. 1. Phloeothrips. 



AA. Last abdominal segment not elongated and tubular in both sexes; 

 both pairs of wings unlike in structure, front wings always veined; 

 margins unequally ciliated; maxillary palpi three- jointed; borer 



in female present Sub-Order II. Terebrantia. 



B. Females with borer curved upwards Fam. II Stenopteridae 



BB, Females with borer curved downwards.. .Fam. III. Coleoptratidee. 



