SULPHUR DIOXIDE AS AN INSECTICIDE. 145 



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

 between 5 and 10 minutes. 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 larva^: 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 Triholiiim confusum Duv. and Silvanus 

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

 tioned Avere asphyxiated witliin 10 minutes; the parasite, protected 

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



(10) Anthrenus vei'hasci L. : Time of asphyxiation not noted, but 

 within 30 minutes. 



oThe 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. 



Diptcra {24 specimens) . 



1 WintJiemia 4-piistii1ata Fab. 5 Sciara sp. 



1 Lucilia ctrsar L. 2 Drosophila pimctulata Loew. 



1 Musca domesiica L. 1 Drosophila busckci Coq. 



2 Culex pipiens L. 3 Ortalids. 



3 Syrphus sp. 5 Unidentified (minute). 



Orthoptera (4 specimens) . 



4 Melanoplus femur-rubriim De G. 



Neuroptera (1 specimen). 



1 Dragon-fly. 



Coleoptera (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 Rh Of/as rileyi Cress. 



Hemiptera (SO specimens) . 



27 Dro'culacephala mollipes Say. 11 Empoasca (2 species). 



2 Deltocephalus inimicus Say. 1 Gcocoris bullatus Say. 



2 Diedroccphala coccinea Forst. 6 Lygus pratensis L. 



3 Stohcra sp. 1 Nobis ferns L. 



22 Cicadula sp. 3 Macrosiphum (?) sp. 

 1 Cicadula sp. 



31024— No. 60—06 m 10 



