10 NORTH AMERICAN THYSANOPTERA. 



includes an outline/ which has been found most satisfactory in his 

 own work. 



Thrips are such minute insects that it is necessary for accurate 

 study that they be mounted on slides. The writer has been able to 

 get the best results by treating them in the following way: The thrips 

 should be collected and killed by dropping them directly into 75 or 80 

 per cent alcohol; they should be dehydrated by passing them succes- 

 sively through 90 per cent, 95 per cent, and absolute alcohol, and then 

 cleared in xylol or cedar oil, and mounted in balsam. One specimen 

 only should be placed under a cover glass; but by using small 

 cover glasses, two can be placed side by side on a single slide. Glycerin 

 jelly mounts are not to be desired. 



The present paper includes 118 species of known American thrips, 

 which are variously divided among 40 genera. Descriptions of 2 

 genera, 10 species, and 1 variety are herewith presented. The 

 bibliography includes only references to recent publications. 



CIASSIFICATION OF NORTH AMERICAN THYSANOPTERA. 



KEY TO THE SUBORDERS AND FAMILIES. 



I. SUBORDER TEREBRANTIA. 



Female with a eawlike ovipositor. Terminal abdominal segment of female conical 

 and of male broadly rounded. Wings usually present; fore pair strongest, 

 with more or less well-developed veins; membrane of wings with micro- 

 scopic hairs. 



a. Antennse with nine segments. Fore wings broad and rounded and with promi- 

 nent ring veins and cross veins. Ovipositor upcurved. 



{A.) Family ^Eolothripid^. 



a' . Antennae with seven, eight, nine, or ten segments. Wings present or want- 

 ing; when present usually narrow and pointed at tips. Ovipositor down- 

 curved {B.) Family Thripid/E. 



' Obder Followed in Describing Thysanoptera. 



Name. 



Measurements: Head length, width; prothorax length, width; mesothorax width; abdomen width; 

 length of tube in the Phloeothripidse; total body length; antenna?, length of segments in microns, total 

 length. Note any variations. 



General color, with variations. 



Head: Comparative size, shape (frons, cheeks), markings, spines. 



Eyes: Size, shape, position on head, color; shape and size of facets; presence or absence of pilosity. 



Ocelli: Present or wanting, size, position, color. 



Mouth-cone: Comparative size, shape; maxillary palpus, shape, segments; labial palpus, shape, seg- 

 ments. 



Antennse: Number of segments, total length compared with head, color, markings including spines, sense 

 cones and areas. 



Prothorax: General shape, size, angles, number and position of spines, color. 



Mesothorax: Shape, comparative size, color. 



Metathorax or pterthorax: Ditto. 



Legs: Shape, markings of claws or spines, color. 



Wings: Fore wings, size, shape, veins, spines or hairs, fringe, color; hind wings, ditto. 



Abdomen: Shape, markings, spines; shape of tube in Phlceothripidte. 



Number of specimens from which described. 



Habitat. 



Food plants. 



Notes: Including time of year when adults are taken. 



Descriptions of males should follow the same outline as for females. 



Notes on larval stages. 



