214 THYSANOPTERA AND ORTHOPTERA. 



Trichothrips tridentatus Shull. — Only two adult specimens were 

 collected. These are deep brown to black, wdth grayish wings over the 

 back. They were accompanied by reddish larvae, doubtless of the same 

 species. 



Taken August 25. 



Habitat. Under scales of bark of white oak. Quercus alba. Reddish 

 larvae, indistingui.shable, apparently, from those which accompanied 

 the adults of this species, -were also found on another white oak over a 

 mile away. This suggests that the species may be somewhat limited 

 in its habitat. 



Phyllothrips aspersus (Hind.s). — This is a long, comparatively 

 slender insect, living tj'pically wholly exposed on leaves. It is brown 

 to black in color. 



Only two specimens taken. July 13. 



Habitat. On leaves of sweet-scented grape, Vitis vulpina. 



Phyllothrips citricornis Hood. — This species resembles the pre- 

 ceding, but can be distinguished by its usually larger size, its much 

 more conspicuous prothoracic spines, and by the fact that the distal 

 three segments of the antenna are lemon yellow, not brown. 



Three specimens taken, July 13. 



Habitat. On leaves of sweet-scented grape, Vitis vulpina. 



Neothrips corticis Hood. — This species is small, compared with 

 most other members of its family. It is of a brown color, and sluggish 

 habits, and lives under bark scales. All the specimens yet known are 

 wingless. 



Taken August 24. 



Habitat. Under scales of bark of American elm, Ulmus americana. 



Allothrips megacephalus Hood.^ — This resembles in a general way 

 the preceding species. There is no easy way of distinguishing the two 

 at a glance. - Under the microscope, however, this species is found to 

 have only seven segments in the antenna; all other members of the 

 family Phloeothripidae have eight segments. 



Taken August 24. 



Habitat. ' Under scales of bark of black ash, Fraxinus nigra. 



Summary of Principal Results. 



1. Twenty-one species of Thysanoptera were taken, of which five were 

 new. 



2. As regards habitat, thrips are of two general ts^pes, (1) those that 

 live in concealed places, and (2) those that live on exposed .surfaces. 



3. The habitat of some species is apparently determined by food; that 

 of others by protection. 



