198 THE CANADIAN ENTOMOLOGIST 



the side of the abdomen and about one-half as long as the hind 

 tarsus; terminal segment of the abdomen, above, in the form of 

 a long, triangular plate with an acute upturned apex, beneath 

 which is the cauda, which is rather narrow and directed down- 

 ward; beak not attaining the second pair of coxse. See figures 

 15 to 20. 



Oviparous ' Female. — The oviparous female differs from the 

 viviparous form in being more robust, a little shorter and brownish 

 or slightly rusty in colour. The antennal joints and other charac- 

 ters are substantially as in the viviparous form. The hind tibi^e 

 are moderately swollen and have 20 or more circular sensoria on 

 their middle one-half. Figures 21-23. 



The eggs are bright green in colour when deposited upon the 

 stems of the host plant, but soon turn shining black on exposure. 

 See figure 24. 



While we have never found this louse abundant, we have 

 seldom had trouble to find examples when looked for at any time 

 during the growing season. 



Explanation of Plate XI. 



Thripsaphis producta. 1, antenna of alate viviparous female; 

 2, vertex and first three joints of antenna of same; 3, eighth tergite 

 of abdomen with cauda and anal plate beneath showing gonapo- 

 physes (a). 



T. verrucosa. 4, vertex showing tubercle. 



T. hallii. 5, antenna of alate female; 6, vertes and antenna 

 of apterous female; 7, terminal segments of oviparous female 

 showing gonapophyses (a), and wax threads (b). 



Saltitsaphis scirpiis. 8, showing terminal segments of abdo- 

 men of apterous female — (a) large bi-lobed 8th tergite, (b) bi- 

 lobed anal plate, (c) knobbed cauda. 



vS. flabella. 9, eighth tergite, bi-lobed anal plate (dotted), 

 and cauda of apterous viviparous female. 



Aspidaphis poly^oni. 10, apterous viviparous female (stem 

 mother?); 11, vertex and antenna of same; 12, cornicle of same; 

 13, cauda of same; 14, lateral view of 8th and 9th segments, (a) 

 8th tergite, (b) cauda, (c) anal plate, (d) genital plate of No. 10; 

 15, alate viviparous female; 16, antenna of same; 17, vertex of 



