Mar., 1903.] Food Plants of Some Bythoscopidae. 
397 
FOOD PLANTS OF SOME BYTHOSCOPIDAE. 
E. I). Bali., Utah Ag. College, Logan, Utah. 
In giving food plant records it seems desirable to distinguish 
those records that are the result of repeated observation, or made 
under circumstances that admit of slight chance for error, from those 
that are based on accidental occurrence of one or more specimens 
upon some given plant. The adults of most all of our leaf-hoppers 
fly very readily and are often found on plants adjacent to the one 
they feed upon, especially after a sweep net has been vigorously 
used in the neighborhood. And too often there is no means of 
knowing whether the record is the result of one accidental speci- 
men or the summation of a life-history study. 
The longer the author studies the food plant relations of the 
Jassidae the more evidence he finds to support the idea that nearly 
every species has its particular food plant or group of closely 
related plants upon which it is almost absolutely dependent in 
part, at least, of its life cycle. In a large number of species the 
larvae rarely if ever leave the plant upon which they emerge from 
the eggs. So that the finding of the larvae in any number upon 
a plant is in a great many cases an almost absolute test of the 
correctness of the food plant determination. 
The following notes are in many cases extracts from almost 
complete life-history studies and in ever}' case are based on suffi- 
cient evidence to almost preclude the idea of an accidental occur- 
rence. 
GENUS MACKOPSIS. 
The following notes complete the food plant list for our forms 
of this genus, with the exception of one species, and while the 
genus as a whole presents a remarkable variety of food plants 
each species seems to be very strictly confined to its particular 
plant or group of closely related forms. In fact I have even 
found the presence of a particular species of Macropsis one of the 
best guides to the determination of the many varieties of one 
plant species. 
M. laeta Uhl. — This species is found only on the bushy species 
of Sumac ( Rhus aromatica and tiilobata'), that occur so commonly 
on the sides of the foot hills and along the bluffs of the streams 
out on the plains in Colorado. The larvae appear early in July, 
hiding in the axils of the leaves and in the fruit clusters. They 
mature early in August, the adults remaining until the middle of 
September. They are of a bright, shining green color and thus 
resemble the petioles and new growth upon which they stay. 
Var. paeta Ball. — Is a pink variety of this species found only in 
the crimson fruit clusters of this Sumac, where it is well protected 
