142 



That of the recorded species there are two at least which must be 

 looked apou as carnivorous, Id certain stages at least. The species 

 here recorded by Mr. Walsh and Dr. Eiley as infesting Phylloxera galls, 

 and the one recorded by Mr. Pergande as destroying Tetranychus. 



The attacks of Thrips upon Fhylloxenv seem explicable to me without 

 supposing them, as Mr. Walsh did, essentially carnivorous. For, sup- 

 posing that they first entered the gall to feed upon the exuded sap there, 

 or the soft tissues so available for their use, it would not be a great 

 change for them to feed upon the exudations from the lice, and later, if 

 pressed for food, upon the lice themselves. This view may be errone- 

 ous, but it seems to me reasonable, though I have been unable to make 

 observations to confirm it, because in all the galls of Phylloxerce I have 

 examined I have not as yet found Thrips present. It seems to me that 

 we must consider the carnivorous diet, where present, as an acquired 

 habit, or one but recently developed in the species, and that for all 

 species upon which no positive observations have been made that the 

 only safe ground to take is that they are a source of danger to culti- 

 vated plants; that is, to believe them injurious until they are proven 

 beneficial. 



The difficulty of making i^ositive observations on the food habits of 

 these minute creatures makes a general law regarding their habits very 

 desirable, and I hope that evidence may accumulate which will enable 

 us to determine still more certainly what is the actual relation which 

 these insects bear to other organisms. 



EXTRACTS FROM CORRESPONDENCE. 



Danger to Human Beings from Use of Paris Green. 



Thanks for Xos. 1 and 2 of "Insect Life." Your publications are great public edu- 

 cators and special aids to farmers. A more thorough knowledge of our friends and 

 foes among insects and birds would increase our farm products. We hope you may 

 find-out insecticides which are less dangerous to humanity than arsenic. Two cases 

 of serious illness, but not fatal, have occurred in our neighborhood — one from eating 

 strawberries planted alternatel}' with potatoes which had been dusted with Parisgreen, 

 and the other from eating raspberries adjoining the potato patch, from which the poison 

 had blown. We hope that Congress will make all necessary appropriations for the 

 carrying on of the good work. — [R. Bingham, Camden, N. J., September 22, 188S. 



Reply. — * ♦ # j j^j^ glad to get the account of the two cases of poisoning from 

 the treatment of potatoes by Paris green, and agree with you that a less dangerous 

 remedy would be good. With proper care, however, there is very little danger, and 

 in both the instances which you mention the application was evidently very care- 

 lessly made. — [September 25, 1888.] 



The Clover Seed-midge in Ohio. 



Will you please tell me the name of the " worms'" that I sent! by the same mail 

 "with this letter? They were in the second crop of clover this season on my brother's 

 faim. He would cut enough of the clover in the morning to feed twelve cows at 



