190 INSTRUCTIONS FOR COLLECTING INSECTS. 



the number referring to its description, in j^encil, on a slip of paper. 

 Thus prepared, it should be dropped into a bottle of alcohol, together 

 with the cocoon and pupa, or pupa alone, if it has no cocoon, treated 

 in a similar manner, and marked with same number. When the 

 student desires to forward his collection to the Smithsonian Institu- 

 tion, the bottles containing the larvae and pupae should have the tops 

 filled with cotton, then completely filled with liquid to prevent the 

 agitation of its contents, and tiglitly corked. TJie name and locality 

 of the collector should be written on the top, as also on the box con- 

 taining perfect insects, and on the copy of his notes. When it is 

 possible to obtain them, at least from three to six specimens of the 

 same species of perfect insects are desirable. 



I would recommend those who are desirous of becoming better 

 acquainted with the subject of entomology, and of acquiring some 

 insight into the classification of Lepidoptera_, to obtain The Introduc- 

 tion to Entomology, by Kirby and Spence, republished by Lea & Blan- 

 chard, Philadelphia, in addition to "A Treatise on some of the 

 Insects of New England which are Injurious to Vegetation. By 

 Thaddeus William Harris, M. D. Boston : Printed by White & 

 Potter." There is also another work published by the State of New 

 York in its natural history series, the chief merit of which, at least 

 with respect to Lepidoptera, consists in its rather indifferent plates. 

 It is much more expensive than Dr. Harris' treatise, and by no means 

 as reliable^, but may enable the student to ascertain the names of some 

 species by comparing the perfect insects with the plates. Besides 

 these works there is also a Catalogue of the North American Sphinges, 

 by Dr. Harris, in the 3Gth volume of Silliman's Journal of Science 

 and Art, 1839; and the Academy of Natural Sciences in Philadelphia 

 will soon publish a synopsis of the same family, representing the 

 present state of its classification, and describing all the new species 

 which have been discovered up to the present time. This can be 

 obtained by students and observers, upon application, for the cost of 

 paper and press-work, which will be comparatively nominal. This 

 paper will be followed by synopses of other families as rapidly as they 

 can be worked up, one of the most serious difficulties being that of 

 obtaining specimens of all the perfect insects described by foreign 

 naturalists. If, therefore, those who intend to collect for the Institu- 

 tion would commence during the present season, and forward to 

 Washington a box of perfect insects from their respective localities, 

 it will facilitate the labors of those engaged at present in the study 

 and hasten the development of this portion of entomological science 

 in the United States. Any observations the student may desire to 

 make public should be transmitted to the Academy of Natural 

 Sciences in Philadelphia for publication in their "■ Proceedings." 



THE PUPAE. 



The larvae that issue from the egg of the perfect insect in early 

 spring reach their full development about its latter portion, and en- 

 tering the pupa state, appear as perfect insects usually in about two or 

 three iveeJcs. The representatives of these, generally speaking, do not 

 become pupae until the beginning of the fall and re.uain in this con- 



