141 



scarcely an opportunity to doubt that they were subsisting upon the 

 plant. A species which agrees with P. nigra Osborn in every respect, 

 so far as I can see, but in larval and pupal characters, occurs commonly 

 on Mullein, and this species I have bred from Qgg to imago with no other 

 food than that received from the mullein leaf, the injury to the leaf 

 showing as yellow blotches, similar to those produced by Tetranychus 

 telarius. I can therefore state positively that this species can mature 

 upon purely vegetable diet. The leaves were kept in water in my office 

 under constant observation, and the Thrips developed to maturity on 

 the same leaves that the Qgg^ were deposited upoii by the adults. 



The following summary of the species whose food habits have been 

 noted will show the state of our knowledge so far as the different species 

 are concerned and the records of which have come to my notice : 



Phloeothrips mali Fitch, f-oiiging iuto youug apples (Fitch). 



PJiliXOthrips caryce Fitch, in hickory galls, food? (Fitch). 



Phlccoihrips nigra Osborn, lives in clover heads. 



Phloeothrips sp. near vigra, feeding on leaves and blossoms of Mullein. 



Phloeothrips frumentaria Bel,, larvae suck grain in the ear (Lindeman). 



Phheothrijys armata Lindeman, aflecting Compositae and Grasses (Lindeman). 



Thrips tritici Fitch, injurious to wheat and clover (Fitch), attacking styles of apple 



blossoms (Osborn), injuring strawberry (various writers). 

 Tlirips cerealium Hal., very destructive to wheat in Europe (Kirby, Curtis, et al.). 

 Thrips minutissimus L., infests potato (Curtis). 

 Thrips ochraceons, destructive to melons, etc. (West wood, Curtis). 

 Tlirips striatus Osborn, "destroys onion plants" (Packard)."^ 

 Thrips sp., very injurious to olive trees (Westwood). 

 Tlirips sp., living on leaves of hop. 



Limolhrips poaphagus Conistock MS., affecting grass (Comstock et ah). 

 Limotlirips graminecb Pergande MS., affects corn, wheat, and grass (Pergande, Forbes 



in lit.). 

 Heliothrips hcemorrhoidalis Bouch^, injuriousin greenhouses and on apple. 

 Heliothrips dracoince, Heg., reported very destructivein hot-houses (Pergande). 

 Heliothrips adonidum -dracwnce (?) infests greenhouse plants (Westwood). 

 Chirothrips autennata Osborn, in timothy heads (Osborn), timothy, wheat, and rye 



(Lindeman). 

 Aptinothrips rufa, subsisting upon Grass and Compositse (Lindeman). 

 Coleothrips trifasciata Fitch, injurious to wheat (Fitch, Packard). 



The conclusion to be drawn from the evidence at hand seems to me as 

 follows : 



That the Thripid?e as a group are normally herbivorous, and their 

 presence on cultivated plants is a source of danger. 



That they feed mainly on the exuded nectar or secretions of plants, 

 when these are abundant, and on pollen, and at such times may do little 

 or no damage. 



That they will upon occasion attack the tissues of the leaves or the 

 essential parts of the blossom and pierce them for their contents, and 

 at such times maj^ cause serious damage. 



* Packard also mentions this species I'Entom. for Beginu,ers, p. 197) as injurious to 

 wheat, but I think it must be an error, and Thrips tritici intended instead. 



