174 [March 



ally those which cover the subcostal vein of the fore wings, I submit it 

 several times to a separate impression, and I finish by brushing away, with 

 the point of a pencil, all the scales that remain on it. Afterwards I place 

 the wings, still wet, between two perfectly equal slips of glass, and secure 

 them with a little wooden vice, [the clothes-pin which opens and closes 

 by means of a spiral spring answers a very good purpose for this use] and 

 bind around the slips a little band of black paper, which I turn over 

 slightly on each end. When all is dry I remove the compressor, and ob- 

 tain thus a very transparent frame, on the side of which I write the name 

 of the species, and which presents, for study, the greatest convenience." 



In order to save space, the contraction " F. w." will be used for Fore 

 wings; and unless the fore wings are specified, the catagories must always 

 be understood to refer to the hind win2;s. 



The " secondary cell" is formed within the disk of the fore wings by a 

 branch from the subcostal vein ; it will sometimes be contracted into 

 " 2nd celir 



The " areole" is a cell formed by the branches of the subcostal vein of 

 the fore wings. 



The " disco central" nervule, is one that rises from the middle of the 

 disk; when on the side of the median vein, it will be called "medio- 

 discal." To save space, the former will sometimes be simply *' the disco- 

 central." 



The " intercostal cell" is formed in the hind wings by a junction be- 

 tween the costal and subcostal veins or a minute communicating vein, 

 when the two are parallel in their course, called the intercostal. 



For all particulars respecting the names of the veins, etc., the student 

 is referred to a paper on the North American Sphinges, contained in the 

 Journ. Acad. Nat. Sci., July, 1859, where the subject is illustrated by 

 figures. 



I reg;ret that I have neither the material nor the time to enable me to 

 give a synopsis of the genera of each of the families. The plan here 

 adopted is perfectly applicable to this purpose ; but it is scarcely the work 

 of one who has a limited collection, and by no means an extended acquaint- 

 ance with genera. For much of the information contained in the various 

 catagories, I have been dependent on various authors, so that I fear that 

 HOW and then a family group may be misplaced under a general heading 

 not applicable to it, or some detail of structure may not be correct. This 

 I am sure the student will overlook, when he considers that this is the 

 first attempt that has been made to arrange analyically the numerous fami- 

 lies of the great group Heterocera. 



