180 JOURNAL OP ECONOMIC ENTOMOLOGY [Vol. 1 



in the forms of Phylloxera vastatnx, which remains throughout life 

 upon the grape, and of Schizoneura lanigera, remaining upon the ap- 

 ple, or of Schizoneura americana, without leaving the elm. 



Do Aphis gossypii and medicaginis Lay Eggs? 



Mr. Pergande mentions two instances where he thinks he may have 

 discovered eggs of gossypii, but from his written statements it seems 

 that he has not seen the sexual forms, and the probability of the eggs 

 found being the eggs of gossypii does not appear to be very strong. 

 For two years we have followed these lice closely without ever finding 

 sexual forms or eggs at any time of the year. During 1906- '07 both 

 these lice were followed all winter upon out-of-door plants by Mr. 

 Bragg, and the present winter they have been followed into December, 

 past several zero nights, and they are still in fine condition, but no 

 males or oviparous females or eggs have been discovered. I would 

 not dare express the opinion that sexual forms never appear in these 

 species, but so far as our observations go, it seems very doubtful about 

 their occurring in Colorado. We shall continue to search carefully 

 for them. 



Food Plants 



As mentioned above, we have seen Aphis oenotherice upon the prim- 

 roses only, and A. carhocolor has been taken by us upon no plants out- 

 side of the genus Eumex. 



Aphis gossypii we have taken colonized from the cotton plant, can- 

 teloupe, muskmelon, watermelon, cucumber, winter squash, pumpkin, 

 the native wild gourd (Cucurbita foetidissima) , Shepherd's purse 

 (Bursa B-pastoris) (which is its favorite plant upon which to spend 

 the winter in Colorado), iron weed {''Ambrosia trifida) , mare's tail 

 {^Erigeron canadensis), Bumex sp. Convolvulus sp., Lepidium vir- 

 ginicum, ^Taraxicum dens-leonis, '^Asclepias sp., and in the summer 

 upon the leaves of buckthorn (Rhamnus cathartica) and Cafalpa 

 speciosa. We have never found it upon strawberry' or purslane, 

 though looked for much upon these plants. Many of the other plants 

 that have been named as the hosts for this species, and which have 

 come under our observation in Colorado, we have found infested by 

 colonies of Aphis medicaginis. I do not mean to say that I think the 

 records that have been given for gossypii on these plants are incorrect, 

 but simply state the results of our observations in Colorado. 



The plants upon which we have observed Aphis medicaginis estab- 

 lished and colonized are: White sweet clover, yellow sweet clover, 



«Found on one plant only. 



