SULPHUR DIOXIDE AS AN INSECTICIDE. 145 



low) : a Most of these insects went down and became motionless in 

 between 5 and 10 minntes. The Orthoptera remained active and 

 uninjured for 15 miutes, but soon thereafter became motionless and 

 apparently asphyxiated. 



(6) Clothes moths, adults: Down and quiet in 10 to 15 minutes. 



(7) Dermestes larvae: Down and quiet in 10 to 15 minutes. 



(8) Ants in jar with earth: Actual time of asphyxiation could 

 not be noted ; probably within 10 minutes, judging from the Hymen- 

 optera in other jars. 



(9) Corn meal containing Tribolium confusum Duv. and Silvanus 

 mrinamensis L., also parasitic four-winged flies: The beetles men- 

 tioned were asphyxiated within 10 minutes; the parasite, protected 

 more or less in the mass of meal, in 30 minutes. 



(10) Anthrenus verbasci L. : Time of asphyxiation not noted, but 

 within 30 minutes. 



a The list of the miscellaneous species subjected to this test, as determined by- 

 Mr. Titus, and in addition to those noted above, follows. It includes 122 speci- 

 mens, representing at least 30 genera. 



Diptera (24 specimens). 



1 Winthemia ^-pustulata Fab. 5 Sciara sp. 



1 Lucilia ccrsar L. 2 Drosophila punctulata Loew. 



1 Musca domcstica L. 1 Drosophila busckei Coq. 



2 Culex pipiens L. 3 Ortalids. 



3 Syrphus sp. 5 Unidentified (minute). 



Orthoptera (4 specimens). 



4 Melanoplus femur-rubrum De G. 



Neuroptera (1 specimen). 

 1 Dragon-fly. 



Goleoptera (10 specimens) . 



3 Minute species. 2 Megilla maculata De G. 



5 Epitrix parvula Fab. 



Hymenoptera (3 specimens). 



1 Halictus sp. 1 Pimpla inquisitor Say. 



1 Rhogas rileyi Cress. 



Hemiptera (80 specimens). 



27 Drwculacephala mollipes Say. 11 Empoasca (2 species). 



2 Deltocephalus inimicus Say. 1 Geocoris bullatus Say. 



2 Diedroccphala coccinea Forst. 6 Lygus pratensis L. 



3 Stobera sp. 1 Nabis ferus L. 



22 Gicadula sp. 3 Macrosiphum (?) sp. 



1 Gicadula sp. 



31024— No. 60—06 m 10 



