THE CANADIAN ENTOMOLOGIST. 19 



and, so far as I can find, all are becoming males, although I find an 

 occasional yellowish-green egg that probably is being deposited by 

 oviparous females upon the stems of the thistle. 



The Canada thistle upon which this louse has been found occurs upon 

 a small area in the suburbs of Fort Collins, where the seeds were intro- 

 duced some twenty years ago. I have never seen the thistle in the 

 surrounding country, and neither Mr. Bragg nor myself have ever found 

 this louse upon other food-plants, but it seems probable that such must 

 occur here. The lice have been most abundant during the month of 

 October, and we have not seen them during the spring or summer months, 

 though carefully searched for. The lice are rather broad and flat, and so 

 near the colour of the leaves of the thistle that they are seen with difficulty 

 unless very numerous. 



Myzus vinccB^ n. sp. (Plate i, figs. 4, 5). 



Alate Viviparous Female {^\g. 5). Type specimens taken'at Fort Collins, 



Nov. II, 1907, upon Vinca sp. in the College greenhouse. 



General colour pale greenish-yellow. Head, antennae, transverse 

 band on pronotum, mesothorax above, laterally and beneath; a transverse 

 band upon each segment of the abdomen dorsally, spots along lateral 

 margins of the abdomen, cauda, subanal and subgenital plates, tarsi, distal 

 ends of femora and tibicC, and beak, except at base, black or blackish ; 

 eyes dark red. Upon segments 3 to 5 of the abdomen the bands unite to 

 form a large blotch. 



Body, 1.70 mm.; antenna, 2.37 mm.; cornicles, .29 mm.; wing, 3.20 

 mm.; cauda, .13 mm. Antennal joints : III .50, IV ,45, V .37, VI .15, 

 VII .73 mm. Cornicles cylindrical, with distinct flange at apex; 3rd joint 

 of antenna with about 15 sensoria that are scarcely tuberculate; no sensoria 

 on joint 4 ; cauda tail-like, upturned ; beak barely reaching 3rd coxi"e ; 

 antennae upon moderate frontal tubercles, the inner sides gibbous, as are 

 the inner sides of the first joints of the antenna ; lateral tubercles of pro- 

 thorax wanting. A few red specks, the eyes of embryo lice, can usually 

 be seen over the abdomen. In some examples segments 2, 3, 4 and 5 of 

 the abdomen have black transverse dashes near their lateral margins. 



Apterous Viviparous Female (Fig. 4). 



Colour light yellowish-green, with black markings above and dark red 

 eyes ; cauda concolorous with body, antenna, legs and cornicles light 

 ydllowish-brown ; distal ends of joints 3, 4 and 5 and all of joints 6 and 

 7 of antenna and extreme ends of cornicles and tarsi black ; distal ends of 

 tibiae slightly infuscated. 



Length of body, 1.90 to 2.1c mm.; antenna, 2.70 to 2.80 mm.; 

 cornicles, .45 mm , cylindrical or slightly enlarged towards base, slightly 



