U. S. D. A., B. E. Tech. Ser. 12, Pt. III. D. F. I. I., April 5, 1907. 



MISCELLANEOUS PAPERS. 



A CONTRIBUTION TO OUR KNOWLEDGE OF THE THYSANOPTERA 



OF CALIFORNIA. 



By Dudley Moulton, Special Agent. 



INTRODUCTION. 



Upon undertaking a stud)' ot" the life history of the pear thrips 

 {E(itJirq>-'<2>yi'')^ inid incidentally of other thrips as the}" came to notice, 

 the writer was impressed by the great deficiency in our knowledge of 

 these insects. In California it seemed, indeed, that new species c^uld 

 be collected on almost every side, and when trying to classify these 

 specimens it was found that the individuals possessed most of the char- 

 acteristics which would place them readily in any certain genus, but 

 that there would often be found striking though minor differences. 

 In several cases it has been necessary to extend the original generic 

 descriptions to include (yalifornia forms. 



In a short published account of California thrips," Miss Daniel 

 states that previous to that time (1904) four species of thrips w-ere 

 known to exist in California. To this number her paper would add 

 five. The writer finds, however, that one of her species, Caliothrips 

 wooclwiorthi, is the already described Heliothrips fasciatns of Per- 

 gande. Thus only eight were known previous to 1906. The writer 

 has been able to gather al)undant specimens of all of these thrips 

 and now adds sixteen more new species and two varieties, making a 

 total of twenty-six. It has been necessary to erect a new genus to 

 incilude the species Orothrijys helloggii. The genus Megnlothrlpx., rep- 

 resented by 3L:galothrips hesperus^ has not before been recorded as 

 found in America. 



Economically considered, the thrips constitute an important group 

 in California, because of the ravages of several species. Growers 

 of deciduous and citrus fruits and of garden truck and nurserymen 

 and florists have sufl'ered at times very considerabl3\ })ut not until 



«New California Thysanoptera. By S. M. Daniel. Ent. News, Vol. X^■, No. 9, 

 pp. 293-297, November, 1904. 



39 



