NO. 1310. 



NORTH AMERICAN THYSANOPTERA— HINDS. 109 



.Eolothripidse this segment is much larger than the others and is 

 drawn out at its hind angles into hooks and processes which apparently 

 assist in copulation. The sexual opening is between the ninth and 

 tenth segments, and frequently from this point there protrudes more 

 or less of the retracted copulatory apparatus, which is usually entirely 

 drawn into the ninth segment through the walls of which 'it can be 

 more or less distinctly seen. Three separate outer parts, which are 

 strongly upcurved, can be seen proceeding from a complex basal part 

 and the entire apparatus is protrusile. Within the abdomen the two 

 elongated, irregularly pear-shaped, orange or brownish colored sper- 

 maries are plainly perceptible, lying usually in about the seventh and 

 eighth segments. Upon the ventral surface of the second to the 

 seventh abdominal segments, inclusive, in many species there arc dis- 

 tinct rounded or transversely elliptical depressions found only in the 

 males. Males are often lighter in color and quicker in movement 

 than the females. 



TUBULIFEKA. 



Female.— ThQ sexual characters of Tul^ulifera are much less distinct 

 and numerous than are those of the other suborder. The end of the 

 abdomen is tubular and the sexual opening is between the ninth and 

 tenth abdominal segments in both sexes. In this region are also found 

 the strictly distinctive characters. In the female the basal edge of 

 the tube is regular and entire. Near the hind edge of the ninth seg- 

 ment below there is a short, strongly chitinized rod (Plate X, fig. 115) 

 which is dark and plainly visible in light colored species, but when 

 the l3ody at this point is nearly opaque, the rod can not be seen and 

 the question of sex is often in doubt. 



jy«/e.-The male is usually smaller and more slender than the female, 

 the sixth, seventh and eighth segments of the abdomen being noticeably 

 narrower. The base of the tube is cut out below in the form of a 

 semicircular notch (Plate X, fig. 114), which can usuallv be plainly 

 seen except in very dark specimens, and through the opening formed 

 by this notch the sexual apparatus can be protruded. The structure 

 of this apparatus is much the same as in the Terebrantia and in light 

 colored specimens it can be seen wholly retracted within the ninth 

 segment. In some species this segment bears a broad scale at the base 

 of the tube. In a few species the sixth segment bears on each side a 

 thick, fleshy, unjointed appendage. The males in manv species have 

 more strongly thickened fore femora and stouter teeth upon the fore 

 tarsi than do the females. 



_ Cojmlation.—Thh I have rarely observed, and therefore the follow- 

 ing statements are mainly gathered from Jordan\s article (306). 



In the Tubulifera the male rests upon the back of the female, and 

 holding firmly to her thorax by his legs, he places the ventral surface 

 ot his abdomen along the side of the abdomen of the female and bends 



