182 TRANSACTIONS OF THE ILLINOIS 



mended, especially where the lice are on fruits or leaves which are to be 

 eaten, as it is both clean and effectual. Another remedy, where the 

 application is on an extensive scale, is dusting the plants with lime ; this 

 is recommended by Dr. Harris for infested potato fields ; I would also 

 suggest it for the Grain Plant-louse {Aphis avence), where found on winter 

 wheat in the fall, or on winter or spring wheat in the spring before gath- 

 ering about the heads. For the latter species Dr. Fitch recommends 

 dusting the grain with dry powder of chloride of lime. 



For the Carrot Plant-louse (Aphis daiici) Curtis recommends dusting 

 powdered tobacco over the crowns early in the morning whilst the dew is 

 upon them, or watering them with a decoction of tobacco. 



The most effective remedy, where it can be applied, is tobacco smoke 

 or the fumes of burning tobacco, sulphur, etc. But to render these suc- 

 cessful the plarft must be covered in some way, so as to confine the smoke 

 or fumes and cause them to penetrate to all parts. A frame, in the shape 

 of a box or bell, covered with cheap cloth of any kind, will answer very 

 well for the flower or vegetable garden, and might be used also for small 

 bushes. 



Various means of using this remedy will suggest themselves in con- 

 nection with the means at hand and the plants to which it is to be applied ; 

 the object to be attained being to confine the smoke of the fumes imme- 

 diately around the lice long enough to suffocate them. Sometimes a 

 minute or two will suffice, where the application is strong and direct ; but 

 usually ten or fifteen minutes, or even longer, will be necessary, where 

 closely confined; but the more diffused the longer time will be required. 



It is possible that an apparatus might be invented for the direct 

 application of tobacco smoke or sulphur fumes, something on the plan of 

 sand-bellows with which painters dust sand over wood work, or similar to 

 the Babcock extinguisher. If it is possible to bring into use, at a reason- 

 able expense, something of this kind sufficiently large to reach, through 

 hose or pipes, the limbs of trees, it would be exceedingly useful, not only 

 against Aphides but numerous other insects. 



Sub-Family Myzoxyun.e. 



I have adopted this name from Serville and Amyot provisionally, to 

 be cast aside when a proper arrangement is given. In the first place, the 

 generic name from which it is derived has become nearly or quite obsolete; 

 and in the second place, this division of the family contains species so 

 widely different in characters and habits that they should be placed in 

 separate groups ; but as I am unable at present, as heretofore stated, to 

 give a correct arrangement, this is given simply as an aid in determining 

 species. If the reader can obtain a correct idea of the distinguishing 

 character of a group, so as to be able to determine whether a given species 

 belongs to it or not, it then becomes much easier for him to determine it. 



As heretofore stated, this group or division of the family is distin- 

 guished from the preceding chiefly by the fact that its species are without 

 honey-tubes or tubercles representing them; and by the veining of the 

 fore wings, the third discoidal vein never being twice forked. 



