BIOLOGICAL COLLECTION'S OF INSECTS. 33 



4. Formation of Biological Collections. 



Several of our leading iustitutions have undertaken, and have 

 made much progress in collections illustrative of the life-histories of 

 our injurious insects, by showing them in all their stages in connec- 

 tion with their depredations, and whatever else may serve to present a 

 knowledge of their lives; as for example, if a moth, the eg^; and shells 

 from which the larva (caterpillar) has emerged; the larva, in each of 

 its 3-6 stages of growth, before and after each molting, preserved in 

 alcohol; larv;u preserved dry, by inflation; larval exuvias; larval ex- 

 crementa; diseased larv» ; the pupa ; cocoon or ground cell, exterior 

 and interior ; pupa-case from which the moth has emerged ; empty 

 cocoon ; perfect insect in its typical form, varieties, aberrations, mon- 

 strosities, etc.; depredations on each of its food-plants ; parasites and 

 other natural enemies, etc. When these collections are connected with 

 agricultural colleges and other institutions for promoting agricul- 

 tural interests, they are usually arranged so as to present for conven- 

 ient inspection all of the insects connected with a particular food-plant. 

 By this method, rather than by following the order of insect clas- 

 sification, one whose wheat-crop has been attacked by an insect un- 

 known to him, should be able, by consulting the cases devoted to wheat 

 insects, to learn the name of the depredator, and at a glance much of 

 its history, habits and changes. The biological collection of the ISTew 

 York State Agricultural Society, prepared by Dr. Fitch during the 

 latter period of his connection with the Society, was arranged upon this 

 plan. The cases contain the following material : Case 1 — Insects in- 

 festing grain and other crops (specifying each principal crop) ; Case 2 — 

 Grass insects ; Case 3 — Insects of the garden (specifying the princi- 

 pal vegetables, flowers, ornamental shrubs, etc.) ; Cases 4 and 5 — In- 

 sects infesting fruit-trees (apple, plum, pear, cherry and quince) ; Case 

 6 — Insects injurious to mau and animals. About IGOO specimens are 

 contained in this collection, while in another series of larger cases are 

 shown the larger biological specimens illustrative of insect depreda- 

 tions on plants, timber, furniture, and books.* 



In the Eatomological Division of the Department of Agriculture at 

 "Washington, now under the direction of Prof. Riley, the commence- 

 ment has been made (by Prof. Comstock) of a biological collection 

 "which shall, as fully as possible, illustrate the investigations of the 

 Department.. It at present contains one hundred and twenty-five 

 ca^-es (double-sided, 31x21 cm.), of which forty-eight are Hemiptera, 

 mainly Cocciclce. illustrating the recent Dapartmeutal studies of these 

 destructive insects. The collection Avill no doubt be rapidly extended, 



*Psi/vhe, ii, 1879, p. 275. 



