BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [120] 



taken, the mortality will frequently amount to 50 percent of the speci- 

 mens. Mr. H. Bakhaus, of Leipsic, thus describes a device which is sub- 

 stantially the base of the vivarium shown on page 114. 



"The base consists of around plate of strong zinc, with two vertical 

 rinis, an inch high, placed one within the other, an inch apart, and 

 soldered to the basal plate so that the outer one is water-tight. The 

 inner rim must be perforated with small holes as close to the bottom 

 as possible. The space inside the inner rim must be filled with fine 

 sand, on which the pup* should be laid. The space between the two 

 rims is then filled with water, which, finding its way through the 

 holes in the inner rim to the sand, causes the necessary moisture. 

 Over the whole is put a bell-shaped cover of wire gauze, which must fit 

 tightly over the outer rim. In this receptacle the pup* remain un- 

 touched, and receive fresh moisture, as above indicated, if required by 

 the drying of the sand." 



The hardy pupa? of most Noctuids and Bombycids, as well as those 

 of many Rophalocera, may be handled with little danger, but other 

 species, if handled at all, or if the cocoons which they make for themselves 

 are broken, can seldom be reared. Constant precautions also must be 

 exercised in the care of the soil and the breeding cages. One of the 

 great drawbacks is the presence of mites and thread worms (Entozoons), 

 etc., which affect dying or dead pup* and larv* in the soil. They also 

 affect living specimens and are capable of doing very considerable 

 damage. To free the soil of them it is necessary at times to allow the 

 earth to become dry enough to be sifted, auo then after removing the 

 pup* submit it to heat sufficient to destroy any undesired lite there 

 may be in it. 



The Insectary. Up to the present time the work of rearing insects has 

 been largely confined to the breeding cage and breeding jar, already de- 

 scribed, which have been kept in the rooms of the investigator. The 

 advantages of having a special building for this purpose are at once 

 apparent and need not be insisted upon. One of the best establish- 

 ments of this kind is that of the Cornell University Experiment Station, 

 which was fully described in Bulletin No. 3, of that station, November, 

 1888. The Kansas Experiment Station has a similar building, and one 

 has recently been built for the useof the Entomological Division of the 

 United States Department of Agriculture. The insect breeding hou.-e. 

 or insectary, should comprise a building having workrooms, or labo- 

 ratories, tor microscopic and general work in the study and preparation 

 of specimens, and also a conservatory for the rearing of specimens and 

 the growth of plants, and, where applied entomology is concerned, 

 special rooms for the preparation and the test of insecticides. The 

 building proper should also have abasement storage room for hibrr 

 nating insects. The laboratory should be, fitted with all the apparatus 

 used in the study of insects, including microscopes and accessories and 

 a dark room for photographic purposes. 



