Mar., 1903.] Food Plants of Some Bythoscopidae. 397 



FOOD PLANTS OF SOME BYTHOSCOPIDAE. 



H. D. Ball, Utah Ag. College, Logan, I'tah. 



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 

 the}' 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-histor}- 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 

 <:orrectness of the food plant determination. 



The following notes are in many cases extracts from almost 

 complete life-history studies and in every case are based on suffi- 

 cient evidence to almost preclude the idea of an accidental occur- 

 rence. 



GENUS MACROPSIS. 



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. 



3/. lacta Uhl. — This species is found only on the bushy species 

 of Sumac {Rims aroii/afica and ti ilobata), 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. pacta Ball, — Is a pink variety of this species found only in 

 the crimson fruit clusters of this Sumac, where it is well protected 



