2^0 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



were carefully collected, placed in a i)ill-box and nej^lected for several 

 days, were found two half-grown syiphus larvae, wbic)i must have been 

 present in the egg state when the lice were placed in the box. Many 

 Chrysojja cocoons were found in the neighborhood of the colonies, and 

 the larvae of Coceinella d-noiata were quite abundant. 



As to remedies, the above-ground colonies are readily destroyed by 

 almost any of the old insect-washes. Their waxy water-proof covering, 

 however, renders it necessary that the application, if very liquid, should 

 be thoroughly applied. The root individuals are almost as difficult to 

 get at as the celel)rated grape phylloxera. A heavy, damp soil seems to be 

 inimical to them, while in a dry, porous soil they flomish. Uence it has 

 been recommended that the earth around the crown of the tree should 

 be kept hollowed into a sort of a basin, in order that the water may col- 

 lect there. It has also been recommended to clear away as much earth 

 as possible from the upi>er roots, and pour on strong soap-suds or hot 

 water. It is very probable that the extensive series of experiments, now 

 being made in France for the purpose of ascertaining an efiective remedy 

 for the phylloxera, wiU bring to light some application which wiU be 

 equally ajjplicable to our apple root lice. 



A NEW PARASITE ON THE CABBAGE PLANT LOUSE. — Numerous Spec- 

 imens of a small hyraenopterous parasite were bred from si)ecimen8 of 

 the well known cabbage plant louse {Aphis hrassicae Linn.), which were 

 received from Mr. Rusha Denise, of Norfolk, Va., February 27, 1880. 

 These parasites proved to belong to an undescribed species. They were 

 referred to Mr. B. T. Cressou, who characterizes them as follows : 



Trioxys picexs Cressou (n. sp.) 



Female, — PiceouB or shining black, smooth and poliKherl, impnnctnred ; clypeus and 

 mandibles duli testafeous, palpi whitish; antennae blavki.sh, sometimes more or less 

 pale beneath, 14-joiiited, the joints faintly fluted or grooved, the last one longest; 

 wings hyaline, subiridesceut, stigma subhyaliue ; legs dull testaceous, Jhe femora and 

 tibia« varied more or less with fuscous; abdomen brown or palepiceous, venter pale. 

 Length, .10 —-.12 inch. 



Male. — Antennae lo'iger, 17-jointed; legs black or fuscous, the anterior pair gen- 

 erally paler, trochanters, base of tibiae and of the tarsi dull testaceous. 



Mab. — Norfolk, Va. Parasitic upon Ajihis brassicae. 



Fungi as insecticides. — The following results, confVnsed from a 

 valuable paper by Prof. A. N. Prentiss, of Cornell University,* may be 

 given as corroborating the results reached by the department in its ex- 

 periments upon Ahtia, and published in the Report on Cotton Insects. 



The writer finds that, although the air of his laboratory and the ad- 

 joining rooms becomes tilled with innumerable spores during the season 

 when mohls, yeast, and other fungi are cultivated by his classes in my- 

 cology, plants growing in the various rooms are often greatly infested 

 with aphides and scale insects which do not appear to be subject to any 

 disease, while on the other hand fungoid disea.ses not rarely attack the 

 plants themselves. From this it appeared improbable that yeast and 

 common molds could be made efficacious in the destruction of noxious 

 insects; but with a view to ascertaining as many facts as possible bear- 

 ing upon the subject, a series of experiments upon house plants, grow- 

 ing under conditions favorable to the growth of fungi, were carried on 

 by Professor Prentiss and his assistant, Mr. Henry. 



Plants infested with aphides scale insects, or red spiders were isolated 

 in various ways and the insects counted, or, where this could not be dune 



* Destruction of Obnoxious Insects by means of Fungoid Growtli," American Nat- 

 uralist, 18r!0. Throuj;h the courtesy of Professor Prentiss, I have been able to study 

 the manuscript of this paper prior to its publicatioo. 



