THE CANADIAN ENTOMOLOGIST. 59 



joints varying considerably. Honey-tubes same general shape as in 

 winged specimen, but longer, extending beyond the tip of the style ; 

 length varying from 1.25 mm. to 2 mm. Style longer and more nearly 

 conical than in winged individuals. Typical form of apterous female is 

 shown in Fig. 5. 



Described from many living and dead viviparous females of both 

 forms from Maryland, New Jersey, Connecticut, Ohio, and Ottawa, Can- 

 ada. Found on green field pea, sweet peas, and kept for a time on 

 clover. Types in formalin and alcohol deposited in the U. S. National 

 Museum. 



General Notes. — I have given this insect much study during the 

 jKist season, and still have a colony under observation (Jan. 29, 1900) in 

 my laboratory. There is no cessation of the reproduction of young. As 

 yet we have not been able to obtain eggs of the species, although several 

 hundred mature apterous females were collected just before our coldest 

 weather late in December and placed in tubes. We also made field 

 observations late in December, and while we had no ditificulty in finding 

 the insects close to the ground on the under side of the leaves of volun- 

 teer peas, we are still in doubt as to how it passes the winter. 1 am of 

 the opinion that, under favorable conditions, the female will continue to 

 reproduce young throughout the winter. That the species will survive 

 severe freezing and reproduce later was conclusively tested in our labora- 

 tory. A colony upon a bunch of peas in water were frozen late in 

 December so that there was ice half an inch thick in the cup. A week 

 later, when heat was again turned on the building, the insects became 

 active and commenced reproduction a few days later. 



Thomas reports a similar case. He observed the wheat-plant louse 

 ( Nectarophora avence) breeding in mid-winter, and took specimens from 

 wheat while the snow was on the ground. 



There is also a probability that the late apterous females deposit 

 eggs. Mr. W. H. Ashmead tells me he has frequently seen the eggs of 

 an allied species, which is abundant on tulip trees about Washington. 

 The eggs are usually deposited about the base of the leaf buds. 



In my breeding experiments and field observations, I have been 

 struck with the seeming absence of hymenopterous parasites upon this 

 insect. Such a condition is quite uncommon where there is such an 

 abundance of plant lice, for, as a rule, they abound. I have bred but a 

 single hymenopterous parasite, Bassus latorius ( $ ), Fab., shown in Fig. 



